Add =~ and !~ operators on strings

`left =~ right` return true if left contains right, using Rust's
`String::contains`. `!~` is the negated version.

A new `apply_operator` function is added which decouples evaluation from
`Value::compare`. This returns a `Value` and opens the door to
implementing `+` for example, though it wouldn't be useful immediately.

The `operator!` macro had to be changed slightly as it would choke on
`~` in arguments.

src/commands/classified/dynamic.rs

@@ -1,5 +1,5 @@
-use crate::parser::hir;
 use derive_new::new;
+use nu_parser::hir;
 
 #[derive(new, Debug, Eq, PartialEq)]
 pub(crate) struct Command {

src/commands/classified/external.rs

@@ -1,9 +1,12 @@
 use super::ClassifiedInputStream;
+use crate::data::value;
 use crate::prelude::*;
 use bytes::{BufMut, BytesMut};
 use futures::stream::StreamExt;
 use futures_codec::{Decoder, Encoder, Framed};
 use log::trace;
+use nu_errors::ShellError;
+use nu_protocol::Value;
 use std::io::{Error, ErrorKind};
 use subprocess::Exec;
 
@@ -105,7 +108,7 @@ impl Command {
             let input_strings = inputs
                 .iter()
                 .map(|i| {
-                    i.as_string().map_err(|_| {
+                    i.as_string().map(|s| s.to_string()).map_err(|_| {
                         let arg = self.args.iter().find(|arg| arg.arg.contains("$it"));
                         if let Some(arg) = arg {
                             ShellError::labeled_error(
@@ -206,9 +209,8 @@ impl Command {
                     let stdout = popen.stdout.take().unwrap();
                     let file = futures::io::AllowStdIo::new(stdout);
                     let stream = Framed::new(file, LinesCodec {});
-                    let stream = stream.map(move |line| {
-                        UntaggedValue::string(line.unwrap()).into_value(&name_tag)
-                    });
+                    let stream =
+                        stream.map(move |line| value::string(line.unwrap()).into_value(&name_tag));
                     Ok(ClassifiedInputStream::from_input_stream(
                         stream.boxed() as BoxStream<'static, Value>
                     ))

src/commands/classified/internal.rs

@@ -1,7 +1,10 @@
-use crate::parser::hir;
+use crate::data::value;
 use crate::prelude::*;
 use derive_new::new;
 use log::{log_enabled, trace};
+use nu_errors::ShellError;
+use nu_parser::hir;
+use nu_protocol::{CommandAction, Primitive, ReturnSuccess, UntaggedValue, Value};
 
 use super::ClassifiedInputStream;
 
@@ -77,7 +80,7 @@ impl Command {
                                 } => {
                                     context.shell_manager.insert_at_current(Box::new(
                                         HelpShell::for_command(
-                                            UntaggedValue::string(cmd).into_value(tag),
+                                            value::string(cmd).into_value(tag),
                                             &context.registry(),
                                         ).unwrap(),
                                     ));
@@ -126,12 +129,12 @@ impl Command {
 
                         doc.render_raw(
                             context.with_host(|host| host.width() - 5),
-                            &mut crate::parser::debug::TermColored::new(&mut buffer),
+                            &mut nu_source::TermColored::new(&mut buffer),
                         ).unwrap();
 
                         let value = String::from_utf8_lossy(buffer.as_slice());
 
-                        yield Ok(UntaggedValue::string(value).into_untagged_value())
+                        yield Ok(value::string(value).into_untagged_value())
                     }
 
                     Err(err) => {

src/commands/classified/mod.rs

@@ -1,5 +1,5 @@
-use crate::parser::{hir, TokenNode};
 use crate::prelude::*;
+use nu_parser::{hir, TokenNode};
 
 mod dynamic;
 mod external;
@@ -11,7 +11,6 @@ pub(crate) use dynamic::Command as DynamicCommand;
 #[allow(unused_imports)]
 pub(crate) use external::{Command as ExternalCommand, ExternalArg, ExternalArgs, StreamNext};
 pub(crate) use internal::Command as InternalCommand;
-pub(crate) use pipeline::Pipeline as ClassifiedPipeline;
 
 pub(crate) struct ClassifiedInputStream {
     pub(crate) objects: InputStream,
@@ -21,7 +20,7 @@ pub(crate) struct ClassifiedInputStream {
 impl ClassifiedInputStream {
     pub(crate) fn new() -> ClassifiedInputStream {
         ClassifiedInputStream {
-            objects: vec![UntaggedValue::nothing().into_untagged_value()].into(),
+            objects: vec![crate::data::value::nothing().into_untagged_value()].into(),
             stdin: None,
         }
     }

src/commands/nth.rs

@@ -1,8 +1,8 @@
 use crate::commands::WholeStreamCommand;
 use crate::context::CommandRegistry;
 use crate::prelude::*;
-use nu_protocol::{Signature, SyntaxShape};
 use nu_errors::ShellError;
+use nu_protocol::{ReturnSuccess, Signature, SyntaxShape};
 use nu_source::Tagged;
 
 #[derive(Deserialize)]

src/data/base.rs

@@ -150,10 +150,10 @@ impl CompareValues {
 }
 
 pub(crate) fn coerce_compare(
-    left: &Value,
-    right: &Value,
+    left: &UntaggedValue,
+    right: &UntaggedValue,
 ) -> Result<CompareValues, (&'static str, &'static str)> {
-    match (&left.value, &right.value) {
+    match (left, right) {
         (UntaggedValue::Primitive(left), UntaggedValue::Primitive(right)) => {
             coerce_compare_primitive(left, right)
         }

src/data/value.rs

@@ -98,8 +98,8 @@ pub fn nothing() -> UntaggedValue {
 
 pub fn compare_values(
     operator: &Operator,
-    left: &Value,
-    right: &Value,
+    left: &UntaggedValue,
+    right: &UntaggedValue,
 ) -> Result<bool, (&'static str, &'static str)> {
     match operator {
         _ => {

src/evaluate/evaluator.rs

@@ -1,13 +1,7 @@
 use crate::context::CommandRegistry;
 use crate::data::base::Block;
 use crate::data::value;
-use crate::errors::ArgumentError;
 use crate::evaluate::operator::apply_operator;
-use crate::parser::hir::path::{ColumnPath, UnspannedPathMember};
-use crate::parser::{
-    hir::{self, Expression, RawExpression},
-    CommandRegistry,
-};
 use crate::prelude::*;
 use crate::TaggedDictBuilder;
 use log::trace;

src/evaluate/operator.rs

@@ -1,6 +1,6 @@
-use crate::data::base::{Primitive, UntaggedValue, Value};
-use crate::parser::Operator;
-use crate::traits::ShellTypeName;
+use crate::data::value;
+use nu_parser::Operator;
+use nu_protocol::{Primitive, ShellTypeName, UntaggedValue, Value};
 use std::ops::Not;
 
 pub fn apply_operator(
@@ -14,12 +14,10 @@ pub fn apply_operator(
         | Operator::LessThan
         | Operator::GreaterThan
         | Operator::LessThanOrEqual
-        | Operator::GreaterThanOrEqual => left.compare(op, right).map(UntaggedValue::boolean),
-        Operator::Dot => Ok(UntaggedValue::boolean(false)),
-        Operator::Contains => contains(left, right).map(UntaggedValue::boolean),
-        Operator::NotContains => contains(left, right)
-            .map(Not::not)
-            .map(UntaggedValue::boolean),
+        | Operator::GreaterThanOrEqual => left.compare(op, right).map(value::boolean),
+        Operator::Dot => Ok(value::boolean(false)),
+        Operator::Contains => contains(left, right).map(value::boolean),
+        Operator::NotContains => contains(left, right).map(Not::not).map(value::boolean),
     }
 }