Add nu-protocol

crates/nu-protocol/src/syntax_shape.rs

@@ -0,0 +1,104 @@
+use crate::Type;
+
+/// The syntactic shapes that values must match to be passed into a command. You can think of this as the type-checking that occurs when you call a function.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum SyntaxShape {
+    /// A specific match to a word or symbol
+    Keyword(Vec<u8>, Box<SyntaxShape>),
+
+    /// Any syntactic form is allowed
+    Any,
+
+    /// Strings and string-like bare words are allowed
+    String,
+
+    /// A dotted path to navigate the table
+    ColumnPath,
+
+    /// A dotted path to navigate the table (including variable)
+    FullColumnPath,
+
+    /// Only a numeric (integer or decimal) value is allowed
+    Number,
+
+    /// A range is allowed (eg, `1..3`)
+    Range,
+
+    /// Only an integer value is allowed
+    Int,
+
+    /// A filepath is allowed
+    FilePath,
+
+    /// A glob pattern is allowed, eg `foo*`
+    GlobPattern,
+
+    /// A block is allowed, eg `{start this thing}`
+    Block,
+
+    /// A table is allowed, eg `[[first, second]; [1, 2]]`
+    Table,
+
+    /// A table is allowed, eg `[first second]`
+    List(Box<SyntaxShape>),
+
+    /// A filesize value is allowed, eg `10kb`
+    Filesize,
+
+    /// A duration value is allowed, eg `19day`
+    Duration,
+
+    /// An operator
+    Operator,
+
+    /// A math expression which expands shorthand forms on the lefthand side, eg `foo > 1`
+    /// The shorthand allows us to more easily reach columns inside of the row being passed in
+    RowCondition,
+
+    /// A general math expression, eg `1 + 2`
+    MathExpression,
+
+    /// A variable name
+    Variable,
+
+    /// A variable with optional type, `x` or `x: int`
+    VarWithOptType,
+
+    /// A signature for a definition, `[x:int, --foo]`
+    Signature,
+
+    /// A general expression, eg `1 + 2` or `foo --bar`
+    Expression,
+}
+
+impl SyntaxShape {
+    pub fn to_type(&self) -> Type {
+        match self {
+            SyntaxShape::Any => Type::Unknown,
+            SyntaxShape::Block => Type::Block,
+            SyntaxShape::ColumnPath => Type::Unknown,
+            SyntaxShape::Duration => Type::Duration,
+            SyntaxShape::Expression => Type::Unknown,
+            SyntaxShape::FilePath => Type::FilePath,
+            SyntaxShape::Filesize => Type::Filesize,
+            SyntaxShape::FullColumnPath => Type::Unknown,
+            SyntaxShape::GlobPattern => Type::String,
+            SyntaxShape::Int => Type::Int,
+            SyntaxShape::List(x) => {
+                let contents = x.to_type();
+                Type::List(Box::new(contents))
+            }
+            SyntaxShape::Keyword(_, expr) => expr.to_type(),
+            SyntaxShape::MathExpression => Type::Unknown,
+            SyntaxShape::Number => Type::Number,
+            SyntaxShape::Operator => Type::Unknown,
+            SyntaxShape::Range => Type::Unknown,
+            SyntaxShape::RowCondition => Type::Bool,
+            SyntaxShape::Signature => Type::Unknown,
+            SyntaxShape::String => Type::String,
+            SyntaxShape::Table => Type::Table,
+            SyntaxShape::VarWithOptType => Type::Unknown,
+            SyntaxShape::Variable => Type::Unknown,
+        }
+    }
+}