nushell/crates/nu-parser/src/hir.rs

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pub(crate) mod baseline_parse;
pub(crate) mod binary;
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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pub(crate) mod expand_external_tokens;
pub(crate) mod external_command;
pub(crate) mod named;
pub(crate) mod path;
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
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pub(crate) mod range;
pub(crate) mod signature;
pub mod syntax_shape;
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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pub(crate) mod tokens_iterator;
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use crate::hir::syntax_shape::Member;
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
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use crate::parse::operator::CompareOperator;
use crate::parse::parser::Number;
use crate::parse::unit::Unit;
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use derive_new::new;
use getset::Getters;
use nu_protocol::{PathMember, ShellTypeName};
use nu_source::{
b, DebugDocBuilder, HasSpan, PrettyDebug, PrettyDebugWithSource, Span, Spanned, SpannedItem,
};
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use serde::{Deserialize, Serialize};
Add support for ~ expansion This ended up being a bit of a yak shave. The basic idea in this commit is to expand `~` in paths, but only in paths. The way this is accomplished is by doing the expansion inside of the code that parses literal syntax for `SyntaxType::Path`. As a quick refresher: every command is entitled to expand its arguments in a custom way. While this could in theory be used for general-purpose macros, today the expansion facility is limited to syntactic hints. For example, the syntax `where cpu > 0` expands under the hood to `where { $it.cpu > 0 }`. This happens because the first argument to `where` is defined as a `SyntaxType::Block`, and the parser coerces binary expressions whose left-hand-side looks like a member into a block when the command is expecting one. This is mildly more magical than what most programming languages would do, but we believe that it makes sense to allow commands to fine-tune the syntax because of the domain nushell is in (command-line shells). The syntactic expansions supported by this facility are relatively limited. For example, we don't allow `$it` to become a bare word, simply because the command asks for a string in the relevant position. That would quickly become more confusing than it's worth. This PR adds a new `SyntaxType` rule: `SyntaxType::Path`. When a command declares a parameter as a `SyntaxType::Path`, string literals and bare words passed as an argument to that parameter are processed using the path expansion rules. Right now, that only means that `~` is expanded into the home directory, but additional rules are possible in the future. By restricting this expansion to a syntactic expansion when passed as an argument to a command expecting a path, we avoid making `~` a generally reserved character. This will also allow us to give good tab completion for paths with `~` characters in them when a command is expecting a path. In order to accomplish the above, this commit changes the parsing functions to take a `Context` instead of just a `CommandRegistry`. From the perspective of macro expansion, you can think of the `CommandRegistry` as a dictionary of in-scope macros, and the `Context` as the compile-time state used in expansion. This could gain additional functionality over time as we find more uses for the expansion system.
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use std::path::PathBuf;
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use crate::parse::tokens::RawNumber;
pub(crate) use self::binary::Binary;
pub(crate) use self::path::Path;
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
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pub(crate) use self::range::Range;
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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pub(crate) use self::syntax_shape::ExpandContext;
pub(crate) use self::tokens_iterator::TokensIterator;
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pub use self::external_command::ExternalCommand;
pub use self::named::{NamedArguments, NamedValue};
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
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#[derive(Debug, Clone)]
pub struct Signature {
unspanned: nu_protocol::Signature,
span: Span,
}
impl Signature {
pub fn new(unspanned: nu_protocol::Signature, span: impl Into<Span>) -> Signature {
Signature {
unspanned,
span: span.into(),
}
}
}
impl HasSpan for Signature {
fn span(&self) -> Span {
self.span
}
}
impl PrettyDebugWithSource for Signature {
fn pretty_debug(&self, source: &str) -> DebugDocBuilder {
self.unspanned.pretty_debug(source)
}
}
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#[derive(Debug, Clone, Eq, PartialEq, Getters, Serialize, Deserialize, new)]
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pub struct Call {
#[get = "pub(crate)"]
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pub head: Box<Expression>,
#[get = "pub(crate)"]
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pub positional: Option<Vec<Expression>>,
#[get = "pub(crate)"]
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pub named: Option<NamedArguments>,
pub span: Span,
}
impl PrettyDebugWithSource for Call {
fn pretty_debug(&self, source: &str) -> DebugDocBuilder {
b::delimit(
"(",
self.head.pretty_debug(source)
+ b::preceded_option(
Some(b::space()),
self.positional.as_ref().map(|pos| {
b::intersperse(pos.iter().map(|expr| expr.pretty_debug(source)), b::space())
}),
)
+ b::preceded_option(
Some(b::space()),
self.named.as_ref().map(|named| named.pretty_debug(source)),
),
")",
)
}
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}
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#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
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pub enum RawExpression {
Literal(Literal),
ExternalWord,
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Synthetic(Synthetic),
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Variable(Variable),
Binary(Box<Binary>),
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
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Range(Box<Range>),
Block(Vec<Expression>),
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List(Vec<Expression>),
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Path(Box<Path>),
Add support for ~ expansion This ended up being a bit of a yak shave. The basic idea in this commit is to expand `~` in paths, but only in paths. The way this is accomplished is by doing the expansion inside of the code that parses literal syntax for `SyntaxType::Path`. As a quick refresher: every command is entitled to expand its arguments in a custom way. While this could in theory be used for general-purpose macros, today the expansion facility is limited to syntactic hints. For example, the syntax `where cpu > 0` expands under the hood to `where { $it.cpu > 0 }`. This happens because the first argument to `where` is defined as a `SyntaxType::Block`, and the parser coerces binary expressions whose left-hand-side looks like a member into a block when the command is expecting one. This is mildly more magical than what most programming languages would do, but we believe that it makes sense to allow commands to fine-tune the syntax because of the domain nushell is in (command-line shells). The syntactic expansions supported by this facility are relatively limited. For example, we don't allow `$it` to become a bare word, simply because the command asks for a string in the relevant position. That would quickly become more confusing than it's worth. This PR adds a new `SyntaxType` rule: `SyntaxType::Path`. When a command declares a parameter as a `SyntaxType::Path`, string literals and bare words passed as an argument to that parameter are processed using the path expansion rules. Right now, that only means that `~` is expanded into the home directory, but additional rules are possible in the future. By restricting this expansion to a syntactic expansion when passed as an argument to a command expecting a path, we avoid making `~` a generally reserved character. This will also allow us to give good tab completion for paths with `~` characters in them when a command is expecting a path. In order to accomplish the above, this commit changes the parsing functions to take a `Context` instead of just a `CommandRegistry`. From the perspective of macro expansion, you can think of the `CommandRegistry` as a dictionary of in-scope macros, and the `Context` as the compile-time state used in expansion. This could gain additional functionality over time as we find more uses for the expansion system.
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FilePath(PathBuf),
ExternalCommand(ExternalCommand),
Command(Span),
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Boolean(bool),
}
impl ShellTypeName for RawExpression {
fn type_name(&self) -> &'static str {
match self {
RawExpression::Literal(literal) => literal.type_name(),
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RawExpression::Synthetic(synthetic) => synthetic.type_name(),
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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RawExpression::Command(..) => "command",
RawExpression::ExternalWord => "external word",
RawExpression::FilePath(..) => "file path",
RawExpression::Variable(..) => "variable",
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RawExpression::List(..) => "list",
RawExpression::Binary(..) => "binary",
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
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RawExpression::Range(..) => "range",
RawExpression::Block(..) => "block",
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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RawExpression::Path(..) => "variable path",
RawExpression::Boolean(..) => "boolean",
RawExpression::ExternalCommand(..) => "external",
}
}
}
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
pub enum Synthetic {
String(String),
}
impl ShellTypeName for Synthetic {
fn type_name(&self) -> &'static str {
match self {
Synthetic::String(_) => "string",
}
}
}
impl RawExpression {
pub fn into_expr(self, span: impl Into<Span>) -> Expression {
Expression {
expr: self,
span: span.into(),
}
}
pub fn into_unspanned_expr(self) -> Expression {
Expression {
expr: self,
span: Span::unknown(),
}
}
}
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
pub struct Expression {
pub expr: RawExpression,
pub span: Span,
}
impl std::ops::Deref for Expression {
type Target = RawExpression;
fn deref(&self) -> &RawExpression {
&self.expr
}
}
impl HasSpan for Expression {
fn span(&self) -> Span {
self.span
}
}
impl PrettyDebugWithSource for Expression {
fn pretty_debug(&self, source: &str) -> DebugDocBuilder {
match &self.expr {
RawExpression::Literal(literal) => literal.spanned(self.span).pretty_debug(source),
RawExpression::ExternalWord => {
b::typed("external word", b::primitive(self.span.slice(source)))
}
RawExpression::Synthetic(s) => match s {
Synthetic::String(s) => b::typed("synthetic", b::primitive(format!("{:?}", s))),
},
RawExpression::Variable(_) => b::keyword(self.span.slice(source)),
RawExpression::Binary(binary) => binary.pretty_debug(source),
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
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RawExpression::Range(range) => range.pretty_debug(source),
RawExpression::Block(_) => b::opaque("block"),
RawExpression::List(list) => b::delimit(
"[",
b::intersperse(
list.iter().map(|item| item.pretty_debug(source)),
b::space(),
),
"]",
),
RawExpression::Path(path) => path.pretty_debug(source),
RawExpression::FilePath(path) => b::typed("path", b::primitive(path.display())),
RawExpression::ExternalCommand(external) => b::typed(
"external command",
b::primitive(external.name.slice(source)),
),
RawExpression::Command(command) => {
b::typed("command", b::primitive(command.slice(source)))
}
RawExpression::Boolean(boolean) => match boolean {
true => b::primitive("$yes"),
false => b::primitive("$no"),
},
}
}
}
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impl Expression {
pub fn number(i: impl Into<Number>, span: impl Into<Span>) -> Expression {
let span = span.into();
RawExpression::Literal(RawLiteral::Number(i.into()).into_literal(span)).into_expr(span)
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}
pub fn size(i: impl Into<Number>, unit: impl Into<Unit>, span: impl Into<Span>) -> Expression {
let span = span.into();
RawExpression::Literal(RawLiteral::Size(i.into(), unit.into()).into_literal(span))
.into_expr(span)
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}
pub fn synthetic_string(s: impl Into<String>) -> Expression {
RawExpression::Synthetic(Synthetic::String(s.into())).into_unspanned_expr()
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}
pub fn string(inner: impl Into<Span>, outer: impl Into<Span>) -> Expression {
let outer = outer.into();
RawExpression::Literal(RawLiteral::String(inner.into()).into_literal(outer))
.into_expr(outer)
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}
pub fn column_path(members: Vec<Member>, span: impl Into<Span>) -> Expression {
let span = span.into();
RawExpression::Literal(RawLiteral::ColumnPath(members).into_literal(span)).into_expr(span)
2019-11-04 16:47:03 +01:00
}
pub fn path(
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
head: Expression,
2019-11-04 16:47:03 +01:00
tail: Vec<impl Into<PathMember>>,
span: impl Into<Span>,
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
) -> Expression {
2019-11-04 16:47:03 +01:00
let tail = tail.into_iter().map(|t| t.into()).collect();
RawExpression::Path(Box::new(Path::new(head, tail))).into_expr(span.into())
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
}
pub fn dot_member(head: Expression, next: impl Into<PathMember>) -> Expression {
let Expression { expr: item, span } = head;
2019-11-04 16:47:03 +01:00
let next = next.into();
let new_span = head.span.until(next.span);
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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match item {
RawExpression::Path(path) => {
let (head, mut tail) = path.parts();
2019-11-04 16:47:03 +01:00
tail.push(next);
Expression::path(head, tail, new_span)
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
}
other => Expression::path(other.into_expr(span), vec![next], new_span),
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
}
}
pub fn infix(
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
left: Expression,
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
op: Spanned<impl Into<CompareOperator>>,
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
right: Expression,
) -> Expression {
let new_span = left.span.until(right.span);
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
RawExpression::Binary(Box::new(Binary::new(left, op.map(|o| o.into()), right)))
.into_expr(new_span)
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
2019-09-18 00:26:27 +02:00
}
Add Range and start Signature support This commit contains two improvements: - Support for a Range syntax (and a corresponding Range value) - Work towards a signature syntax Implementing the Range syntax resulted in cleaning up how operators in the core syntax works. There are now two kinds of infix operators - tight operators (`.` and `..`) - loose operators Tight operators may not be interspersed (`$it.left..$it.right` is a syntax error). Loose operators require whitespace on both sides of the operator, and can be arbitrarily interspersed. Precedence is left to right in the core syntax. Note that delimited syntax (like `( ... )` or `[ ... ]`) is a single token node in the core syntax. A single token node can be parsed from beginning to end in a context-free manner. The rule for `.` is `<token node>.<member>`. The rule for `..` is `<token node>..<token node>`. Loose operators all have the same syntactic rule: `<token node><space><loose op><space><token node>`. The second aspect of this pull request is the beginning of support for a signature syntax. Before implementing signatures, a necessary prerequisite is for the core syntax to support multi-line programs. That work establishes a few things: - `;` and newlines are handled in the core grammar, and both count as "separators" - line comments begin with `#` and continue until the end of the line In this commit, multi-token productions in the core grammar can use separators interchangably with spaces. However, I think we will ultimately want a different rule preventing separators from occurring before an infix operator, so that the end of a line is always unambiguous. This would avoid gratuitous differences between modules and repl usage. We already effectively have this rule, because otherwise `x<newline> | y` would be a single pipeline, but of course that wouldn't work.
2019-12-04 22:14:52 +01:00
pub fn range(left: Expression, op: Span, right: Expression) -> Expression {
let new_span = left.span.until(right.span);
RawExpression::Range(Box::new(Range::new(left, op, right))).into_expr(new_span)
}
pub fn file_path(path: impl Into<PathBuf>, outer: impl Into<Span>) -> Expression {
RawExpression::FilePath(path.into()).into_expr(outer)
Add support for ~ expansion This ended up being a bit of a yak shave. The basic idea in this commit is to expand `~` in paths, but only in paths. The way this is accomplished is by doing the expansion inside of the code that parses literal syntax for `SyntaxType::Path`. As a quick refresher: every command is entitled to expand its arguments in a custom way. While this could in theory be used for general-purpose macros, today the expansion facility is limited to syntactic hints. For example, the syntax `where cpu > 0` expands under the hood to `where { $it.cpu > 0 }`. This happens because the first argument to `where` is defined as a `SyntaxType::Block`, and the parser coerces binary expressions whose left-hand-side looks like a member into a block when the command is expecting one. This is mildly more magical than what most programming languages would do, but we believe that it makes sense to allow commands to fine-tune the syntax because of the domain nushell is in (command-line shells). The syntactic expansions supported by this facility are relatively limited. For example, we don't allow `$it` to become a bare word, simply because the command asks for a string in the relevant position. That would quickly become more confusing than it's worth. This PR adds a new `SyntaxType` rule: `SyntaxType::Path`. When a command declares a parameter as a `SyntaxType::Path`, string literals and bare words passed as an argument to that parameter are processed using the path expansion rules. Right now, that only means that `~` is expanded into the home directory, but additional rules are possible in the future. By restricting this expansion to a syntactic expansion when passed as an argument to a command expecting a path, we avoid making `~` a generally reserved character. This will also allow us to give good tab completion for paths with `~` characters in them when a command is expecting a path. In order to accomplish the above, this commit changes the parsing functions to take a `Context` instead of just a `CommandRegistry`. From the perspective of macro expansion, you can think of the `CommandRegistry` as a dictionary of in-scope macros, and the `Context` as the compile-time state used in expansion. This could gain additional functionality over time as we find more uses for the expansion system.
2019-08-26 21:21:03 +02:00
}
pub fn list(list: Vec<Expression>, span: impl Into<Span>) -> Expression {
RawExpression::List(list).into_expr(span)
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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}
pub fn bare(span: impl Into<Span>) -> Expression {
let span = span.into();
RawExpression::Literal(RawLiteral::Bare.into_literal(span)).into_expr(span)
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}
pub fn pattern(inner: impl Into<String>, outer: impl Into<Span>) -> Expression {
let outer = outer.into();
RawExpression::Literal(RawLiteral::GlobPattern(inner.into()).into_literal(outer))
.into_expr(outer)
}
pub fn variable(inner: impl Into<Span>, outer: impl Into<Span>) -> Expression {
RawExpression::Variable(Variable::Other(inner.into())).into_expr(outer)
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}
pub fn external_command(inner: impl Into<Span>, outer: impl Into<Span>) -> Expression {
RawExpression::ExternalCommand(ExternalCommand::new(inner.into())).into_expr(outer)
}
pub fn it_variable(inner: impl Into<Span>, outer: impl Into<Span>) -> Expression {
RawExpression::Variable(Variable::It(inner.into())).into_expr(outer)
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}
}
impl From<Spanned<Path>> for Expression {
fn from(path: Spanned<Path>) -> Expression {
RawExpression::Path(Box::new(path.item)).into_expr(path.span)
}
}
/// Literals are expressions that are:
///
/// 1. Copy
/// 2. Can be evaluated without additional context
/// 3. Evaluation cannot produce an error
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
pub enum RawLiteral {
Number(Number),
Size(Number, Unit),
String(Span),
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GlobPattern(String),
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ColumnPath(Vec<Member>),
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Bare,
}
impl RawLiteral {
pub fn into_literal(self, span: impl Into<Span>) -> Literal {
Literal {
literal: self,
span: span.into(),
}
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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}
}
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
pub struct Literal {
pub literal: RawLiteral,
pub span: Span,
Overhaul the expansion system The main thrust of this (very large) commit is an overhaul of the expansion system. The parsing pipeline is: - Lightly parse the source file for atoms, basic delimiters and pipeline structure into a token tree - Expand the token tree into a HIR (high-level intermediate representation) based upon the baseline syntax rules for expressions and the syntactic shape of commands. Somewhat non-traditionally, nu doesn't have an AST at all. It goes directly from the token tree, which doesn't represent many important distinctions (like the difference between `hello` and `5KB`) directly into a high-level representation that doesn't have a direct correspondence to the source code. At a high level, nu commands work like macros, in the sense that the syntactic shape of the invocation of a command depends on the definition of a command. However, commands do not have the ability to perform unrestricted expansions of the token tree. Instead, they describe their arguments in terms of syntactic shapes, and the expander expands the token tree into HIR based upon that definition. For example, the `where` command says that it takes a block as its first required argument, and the description of the block syntactic shape expands the syntax `cpu > 10` into HIR that represents `{ $it.cpu > 10 }`. This commit overhauls that system so that the syntactic shapes are described in terms of a few new traits (`ExpandSyntax` and `ExpandExpression` are the primary ones) that are more composable than the previous system. The first big win of this new system is the addition of the `ColumnPath` shape, which looks like `cpu."max ghz"` or `package.version`. Previously, while a variable path could look like `$it.cpu."max ghz"`, the tail of a variable path could not be easily reused in other contexts. Now, that tail is its own syntactic shape, and it can be used as part of a command's signature. This cleans up commands like `inc`, `add` and `edit` as well as shorthand blocks, which can now look like `| where cpu."max ghz" > 10`
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}
impl ShellTypeName for Literal {
fn type_name(&self) -> &'static str {
match &self.literal {
RawLiteral::Number(..) => "number",
RawLiteral::Size(..) => "size",
RawLiteral::String(..) => "string",
RawLiteral::ColumnPath(..) => "column path",
RawLiteral::Bare => "string",
RawLiteral::GlobPattern(_) => "pattern",
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}
}
}
impl PrettyDebugWithSource for Literal {
fn pretty_debug(&self, source: &str) -> DebugDocBuilder {
match &self.literal {
RawLiteral::Number(number) => number.pretty(),
RawLiteral::Size(number, unit) => (number.pretty() + unit.pretty()).group(),
RawLiteral::String(string) => b::primitive(format!("{:?}", string.slice(source))),
RawLiteral::GlobPattern(pattern) => b::typed("pattern", b::primitive(pattern)),
RawLiteral::ColumnPath(path) => b::typed(
"column path",
b::intersperse_with_source(path.iter(), b::space(), source),
),
RawLiteral::Bare => b::primitive(self.span.slice(source)),
}
}
}
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#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Serialize, Deserialize)]
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pub enum Variable {
It(Span),
Other(Span),
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}