Add --regex flag to parse (#1863)

crates/nu-cli/tests/commands/parse.rs

@@ -1,11 +1,11 @@
-use nu_test_support::fs::Stub::FileWithContentToBeTrimmed;
+use nu_test_support::fs::Stub;
 use nu_test_support::playground::Playground;
 use nu_test_support::{nu, pipeline};
 
 #[test]
 fn extracts_fields_from_the_given_the_pattern() {
     Playground::setup("parse_test_1", |dirs, sandbox| {
-        sandbox.with_files(vec![FileWithContentToBeTrimmed(
+        sandbox.with_files(vec![Stub::FileWithContentToBeTrimmed(
             "key_value_separated_arepa_ingredients.txt",
             r#"
                 VAR1=Cheese
@@ -28,3 +28,77 @@ fn extracts_fields_from_the_given_the_pattern() {
         assert_eq!(actual.out, "JonathanParsed");
     })
 }
+
+mod regex {
+    use super::*;
+
+    fn nushell_git_log_oneline<'a>() -> Vec<Stub<'a>> {
+        vec![Stub::FileWithContentToBeTrimmed(
+            "nushell_git_log_oneline.txt",
+            r#"
+                ae87582c Fix missing invocation errors (#1846)
+                b89976da let format access variables also (#1842)
+            "#,
+        )]
+    }
+
+    #[test]
+    fn extracts_fields_with_all_named_groups() {
+        Playground::setup("parse_test_regex_1", |dirs, sandbox| {
+            sandbox.with_files(nushell_git_log_oneline());
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                open nushell_git_log_oneline.txt
+                | parse --regex "(?P<Hash>\w+) (?P<Message>.+) \(#(?P<PR>\d+)\)"
+                | nth 1
+                | get PR
+                | echo $it
+            "#
+            ));
+
+            assert_eq!(actual.out, "1842");
+        })
+    }
+
+    #[test]
+    fn extracts_fields_with_all_unnamed_groups() {
+        Playground::setup("parse_test_regex_2", |dirs, sandbox| {
+            sandbox.with_files(nushell_git_log_oneline());
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                open nushell_git_log_oneline.txt
+                | parse --regex "(\w+) (.+) \(#(\d+)\)"
+                | nth 1
+                | get Capture1
+                | echo $it
+            "#
+            ));
+
+            assert_eq!(actual.out, "b89976da");
+        })
+    }
+
+    #[test]
+    fn extracts_fields_with_named_and_unnamed_groups() {
+        Playground::setup("parse_test_regex_3", |dirs, sandbox| {
+            sandbox.with_files(nushell_git_log_oneline());
+
+            let actual = nu!(
+                cwd: dirs.test(), pipeline(
+                r#"
+                open nushell_git_log_oneline.txt
+                | parse --regex "(?P<Hash>\w+) (.+) \(#(?P<PR>\d+)\)"
+                | nth 1
+                | get Capture2
+                | echo $it
+            "#
+            ));
+
+            assert_eq!(actual.out, "let format access variables also");
+        })
+    }
+}

crates/nu_plugin_parse/src/lib.rs

@@ -1,4 +1,4 @@
 mod nu;
 mod parse;
 
-pub use parse::Parse;
+pub use parse::{ColumnNames, Parse};

crates/nu_plugin_parse/src/nu/mod.rs

@@ -5,12 +5,13 @@ use nu_protocol::{
     UntaggedValue, Value,
 };
 
-use crate::Parse;
+use crate::{ColumnNames, Parse};
 use regex::Regex;
 
 impl Plugin for Parse {
     fn config(&mut self) -> Result<Signature, ShellError> {
         Ok(Signature::build("parse")
+            .switch("regex", "use full regex syntax for patterns", Some('r'))
             .required(
                 "pattern",
                 SyntaxShape::String,
@@ -20,24 +21,34 @@ impl Plugin for Parse {
     }
 
     fn begin_filter(&mut self, call_info: CallInfo) -> Result<Vec<ReturnValue>, ShellError> {
-        if let Some(args) = call_info.args.positional {
+        if let Some(ref args) = &call_info.args.positional {
             match &args[0] {
                 Value {
                     value: UntaggedValue::Primitive(Primitive::String(s)),
                     tag,
                 } => {
                     self.pattern_tag = tag.clone();
-                    let parse_pattern = parse(&s);
-                    let parse_regex = build_regex(&parse_pattern);
-                    self.column_names = column_names(&parse_pattern);
-
-                    self.regex = Regex::new(&parse_regex).map_err(|_| {
-                        ShellError::labeled_error(
-                            "Could not parse regex",
-                            "could not parse regex",
-                            tag.span,
-                        )
-                    })?;
+                    if call_info.args.has("regex") {
+                        self.regex = Regex::new(&s).map_err(|_| {
+                            ShellError::labeled_error(
+                                "Could not parse regex",
+                                "could not parse regex",
+                                tag.span,
+                            )
+                        })?;
+                        self.column_names = ColumnNames::from(&self.regex);
+                    } else {
+                        let parse_pattern = parse(&s);
+                        let parse_regex = build_regex(&parse_pattern);
+                        self.column_names = ColumnNames::from(parse_pattern.as_slice());
+                        self.regex = Regex::new(&parse_regex).map_err(|_| {
+                            ShellError::labeled_error(
+                                "Could not parse regex",
+                                "could not parse regex",
+                                tag.span,
+                            )
+                        })?;
+                    };
                 }
                 Value { tag, .. } => {
                     return Err(ShellError::labeled_error(
@@ -58,11 +69,11 @@ impl Plugin for Parse {
                 for caps in self.regex.captures_iter(&s) {
                     let group_count = caps.len() - 1;
 
-                    if self.column_names.len() != group_count {
+                    if self.column_names.0.len() != group_count {
                         return Err(ShellError::labeled_error(
                             format!(
                                 "There are {} column(s) specified in the pattern, but could only match the first {}: [{}]",
-                                self.column_names.len(),
+                                self.column_names.0.len(),
                                 group_count,
                                 caps.iter()
                                     .skip(1)
@@ -89,7 +100,7 @@ impl Plugin for Parse {
                     }
 
                     let mut dict = TaggedDictBuilder::new(&input.tag);
-                    for (idx, column_name) in self.column_names.iter().enumerate() {
+                    for (idx, column_name) in self.column_names.0.iter().enumerate() {
                         dict.insert_untagged(
                             column_name,
                             UntaggedValue::string(caps[idx + 1].to_string()),
@@ -150,16 +161,30 @@ fn parse(input: &str) -> Vec<ParseCommand> {
     output
 }
 
-fn column_names(commands: &[ParseCommand]) -> Vec<String> {
-    let mut output = vec![];
+impl From<&[ParseCommand]> for ColumnNames {
+    fn from(commands: &[ParseCommand]) -> ColumnNames {
+        let mut output = vec![];
 
-    for command in commands {
-        if let ParseCommand::Column(c) = command {
-            output.push(c.clone());
+        for command in commands {
+            if let ParseCommand::Column(c) = command {
+                output.push(c.clone());
+            }
         }
-    }
 
-    output
+        ColumnNames(output)
+    }
+}
+
+impl From<&Regex> for ColumnNames {
+    fn from(regex: &Regex) -> ColumnNames {
+        let output = regex
+            .capture_names()
+            .enumerate()
+            .skip(1)
+            .map(|(i, name)| name.map(String::from).unwrap_or(format!("Capture{}", i)))
+            .collect::<Vec<_>>();
+        ColumnNames(output)
+    }
 }
 
 fn build_regex(commands: &[ParseCommand]) -> String {

crates/nu_plugin_parse/src/parse.rs

@@ -5,9 +5,11 @@ pub struct Parse {
     pub regex: Regex,
     pub name: Tag,
     pub pattern_tag: Tag,
-    pub column_names: Vec<String>,
+    pub column_names: ColumnNames,
 }
 
+pub struct ColumnNames(pub Vec<String>);
+
 impl Parse {
     #[allow(clippy::trivial_regex)]
     pub fn new() -> Result<Self, Box<dyn std::error::Error>> {
@@ -15,7 +17,7 @@ impl Parse {
             regex: Regex::new("")?,
             name: Tag::unknown(),
             pattern_tag: Tag::unknown(),
-            column_names: vec![],
+            column_names: ColumnNames(vec![]),
         })
     }
 }