fileset, revset, templater: add support for single-quoted raw string literals

Since fileset/revset/template expressions are specified as command-line
arguments, it's sometimes convenient to use single quotes instead of double
quotes. Various scripting languages parse single-quoted strings in various ways,
but I choose the TOML rule because it's simple and practically useful. TOML is
our config language, so copying the TOML syntax would be less surprising than
borrowing it from another language.

https://github.com/toml-lang/toml/issues/188

CHANGELOG.md

@@ -35,6 +35,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   expressions](docs/filesets.md). Note that filesets are currently experimental,
   but will be enabled by default in a future release.
 
+* Revsets and templates now support single-quoted raw string literals.
+
 * `jj prev` and `jj next` now work when the working copy revision is a merge.
 
 * Operation objects in templates now have a `snapshot() -> Boolean` method that

cli/src/template.pest

@@ -24,6 +24,9 @@ string_content_char = @{ !("\"" | "\\") ~ ANY }
 string_content = @{ string_content_char+ }
 string_literal = ${ "\"" ~ (string_content | string_escape)* ~ "\"" }
 
+raw_string_content = @{ (!"'" ~ ANY)* }
+raw_string_literal = ${ "'" ~ raw_string_content ~ "'" }
+
 integer_literal = @{
   ASCII_NONZERO_DIGIT ~ ASCII_DIGIT*
   | "0"
@@ -59,6 +62,7 @@ primary = _{
   | lambda
   | identifier
   | string_literal
+  | raw_string_literal
   | integer_literal
 }
 

cli/src/template_parser.rs

@@ -42,6 +42,8 @@ impl Rule {
             Rule::string_content_char => None,
             Rule::string_content => None,
             Rule::string_literal => None,
+            Rule::raw_string_content => None,
+            Rule::raw_string_literal => None,
             Rule::integer_literal => None,
             Rule::identifier => None,
             Rule::concat_op => Some("++"),
@@ -383,6 +385,12 @@ fn parse_term_node(pair: Pair<Rule>) -> TemplateParseResult<ExpressionNode> {
             let text = STRING_LITERAL_PARSER.parse(expr.into_inner());
             ExpressionNode::new(ExpressionKind::String(text), span)
         }
+        Rule::raw_string_literal => {
+            let (content,) = expr.into_inner().collect_tuple().unwrap();
+            assert_eq!(content.as_rule(), Rule::raw_string_content);
+            let text = content.as_str().to_owned();
+            ExpressionNode::new(ExpressionKind::String(text), span)
+        }
         Rule::integer_literal => {
             let value = expr.as_str().parse().map_err(|err| {
                 TemplateParseError::expression("Invalid integer literal", span).with_source(err)
@@ -1178,6 +1186,24 @@ mod tests {
             parse_into_kind(r#" "\y" "#),
             Err(TemplateParseErrorKind::SyntaxError),
         );
+
+        // Single-quoted raw string
+        assert_eq!(
+            parse_into_kind(r#" '' "#),
+            Ok(ExpressionKind::String("".to_owned())),
+        );
+        assert_eq!(
+            parse_into_kind(r#" 'a\n' "#),
+            Ok(ExpressionKind::String(r"a\n".to_owned())),
+        );
+        assert_eq!(
+            parse_into_kind(r#" '\' "#),
+            Ok(ExpressionKind::String(r"\".to_owned())),
+        );
+        assert_eq!(
+            parse_into_kind(r#" '"' "#),
+            Ok(ExpressionKind::String(r#"""#.to_owned())),
+        );
     }
 
     #[test]

docs/filesets.md

@@ -13,14 +13,16 @@ ui.allow-filesets = true
 ```
 
 Many `jj` commands accept fileset expressions as positional arguments. File
-names passed to these commands must be quoted if they contain whitespace or meta
-characters. However, as a special case, quotes can be omitted if the expression
-has no operators nor function calls. For example:
+names passed to these commands [must be quoted][string-literals] if they contain
+whitespace or meta characters. However, as a special case, quotes can be omitted
+if the expression has no operators nor function calls. For example:
 
 * `jj diff 'Foo Bar'` (shell quotes are required, but inner quotes are optional)
 * `jj diff '~"Foo Bar"'` (both shell and inner quotes are required)
 * `jj diff '"Foo(1)"'` (both shell and inner quotes are required)
 
+[string-literals]: templates.md#string-literals
+
 ## File patterns
 
 The following patterns are supported:

docs/revsets.md

@@ -29,10 +29,12 @@ A full change ID refers to all visible commits with that change ID (there is
 typically only one visible commit with a given change ID). A unique prefix of
 the full change ID can also be used. It is an error to use a non-unique prefix.
 
-Use double quotes to prevent a symbol from being interpreted as an expression.
-For example, `"x-"` is the symbol `x-`, not the parents of symbol `x`.
-Taking shell quoting into account, you may need to use something like
-`jj log -r '"x-"'`.
+Use [single or double quotes][string-literals] to prevent a symbol from being
+interpreted as an expression. For example, `"x-"` is the symbol `x-`, not the
+parents of symbol `x`. Taking shell quoting into account, you may need to use
+something like `jj log -r '"x-"'`.
+
+[string-literals]: templates.md#string-literals
 
 ### Priority
 

docs/templates.md

@@ -194,11 +194,22 @@ defined.
 
 #### String literals
 
-String literals must be surrounded by double quotes (`"`). The following escape
-sequences starting with a backslash have their usual meaning: `\"`, `\\`, `\n`,
-`\r`, `\t`, `\0`. Other escape sequences are not supported. Any UTF-8 characters
-are allowed inside a string literal, with two exceptions: unescaped `"`-s and
-uses of `\` that don't form a valid escape sequence.
+String literals must be surrounded by single or double quotes (`'` or `"`).
+A double-quoted string literal supports the following escape sequences:
+
+* `\"`: double quote
+* `\\`: backslash
+* `\t`: horizontal tab
+* `\r`: carriage return
+* `\n`: new line
+* `\0`: null
+
+Other escape sequences are not supported. Any UTF-8 characters are allowed
+inside a string literal, with two exceptions: unescaped `"`-s and uses of `\`
+that don't form a valid escape sequence.
+
+A single-quoted string literal has no escape syntax. `'` can't be expressed
+inside a single-quoted string literal.
 
 ### Template type
 

lib/src/fileset.pest

@@ -40,6 +40,9 @@ string_content_char = @{ !("\"" | "\\") ~ ANY }
 string_content = @{ string_content_char+ }
 string_literal = ${ "\"" ~ (string_content | string_escape)* ~ "\"" }
 
+raw_string_content = @{ (!"'" ~ ANY)* }
+raw_string_literal = ${ "'" ~ raw_string_content ~ "'" }
+
 pattern_kind_op = { ":" }
 
 negate_op = { "~" }
@@ -57,7 +60,11 @@ function_arguments = {
 }
 
 // TODO: change rhs to string_literal to require quoting? #2101
-string_pattern = { strict_identifier ~ pattern_kind_op ~ (identifier | string_literal) }
+string_pattern = {
+  strict_identifier
+  ~ pattern_kind_op
+  ~ (identifier | string_literal | raw_string_literal)
+}
 bare_string_pattern = { strict_identifier ~ pattern_kind_op ~ bare_string }
 
 primary = {
@@ -66,6 +73,7 @@ primary = {
   | string_pattern
   | identifier
   | string_literal
+  | raw_string_literal
 }
 
 expression = {

lib/src/fileset_parser.rs

@@ -48,6 +48,8 @@ impl Rule {
             Rule::string_content_char => None,
             Rule::string_content => None,
             Rule::string_literal => None,
+            Rule::raw_string_content => None,
+            Rule::raw_string_literal => None,
             Rule::pattern_kind_op => Some(":"),
             Rule::negate_op => Some("~"),
             Rule::union_op => Some("|"),
@@ -233,6 +235,11 @@ fn parse_as_string_literal(pair: Pair<Rule>) -> String {
     match pair.as_rule() {
         Rule::identifier => pair.as_str().to_owned(),
         Rule::string_literal => STRING_LITERAL_PARSER.parse(pair.into_inner()),
+        Rule::raw_string_literal => {
+            let (content,) = pair.into_inner().collect_tuple().unwrap();
+            assert_eq!(content.as_rule(), Rule::raw_string_content);
+            content.as_str().to_owned()
+        }
         r => panic!("unexpected string literal rule: {r:?}"),
     }
 }
@@ -256,7 +263,9 @@ fn parse_primary_node(pair: Pair<Rule>) -> FilesetParseResult<ExpressionNode> {
             ExpressionKind::StringPattern { kind, value }
         }
         Rule::identifier => ExpressionKind::Identifier(first.as_str()),
-        Rule::string_literal => ExpressionKind::String(parse_as_string_literal(first)),
+        Rule::string_literal | Rule::raw_string_literal => {
+            ExpressionKind::String(parse_as_string_literal(first))
+        }
         r => panic!("unexpected primary rule: {r:?}"),
     };
     Ok(ExpressionNode::new(expr, span))
@@ -468,6 +477,24 @@ mod tests {
             parse_into_kind(r#" "\y" "#),
             Err(FilesetParseErrorKind::SyntaxError)
         );
+
+        // Single-quoted raw string
+        assert_eq!(
+            parse_into_kind(r#" '' "#),
+            Ok(ExpressionKind::String("".to_owned())),
+        );
+        assert_eq!(
+            parse_into_kind(r#" 'a\n' "#),
+            Ok(ExpressionKind::String(r"a\n".to_owned())),
+        );
+        assert_eq!(
+            parse_into_kind(r#" '\' "#),
+            Ok(ExpressionKind::String(r"\".to_owned())),
+        );
+        assert_eq!(
+            parse_into_kind(r#" '"' "#),
+            Ok(ExpressionKind::String(r#"""#.to_owned())),
+        );
     }
 
     #[test]
@@ -493,6 +520,13 @@ mod tests {
                 value: "".to_owned()
             })
         );
+        assert_eq!(
+            parse_into_kind(r#" foo:'\' "#),
+            Ok(ExpressionKind::StringPattern {
+                kind: "foo",
+                value: r"\".to_owned()
+            })
+        );
         assert_eq!(
             parse_into_kind(r#" foo: "#),
             Err(FilesetParseErrorKind::SyntaxError)

lib/src/revset.pest

@@ -21,6 +21,7 @@ identifier = @{
 symbol = {
   identifier
   | string_literal
+  | raw_string_literal
 }
 
 string_escape = @{ "\\" ~ ("t" | "r" | "n" | "0" | "\"" | "\\") }
@@ -28,6 +29,9 @@ string_content_char = @{ !("\"" | "\\") ~ ANY }
 string_content = @{ string_content_char+ }
 string_literal = ${ "\"" ~ (string_content | string_escape)* ~ "\"" }
 
+raw_string_content = @{ (!"'" ~ ANY)* }
+raw_string_literal = ${ "'" ~ raw_string_content ~ "'" }
+
 at_op = { "@" }
 pattern_kind_op = { ":" }
 

lib/src/revset.rs

@@ -108,6 +108,8 @@ impl Rule {
             Rule::string_content_char => None,
             Rule::string_content => None,
             Rule::string_literal => None,
+            Rule::raw_string_content => None,
+            Rule::raw_string_literal => None,
             Rule::at_op => Some("@"),
             Rule::pattern_kind_op => Some(":"),
             Rule::parents_op => Some("-"),
@@ -1114,6 +1116,11 @@ fn parse_symbol_rule_as_literal(mut pairs: Pairs<Rule>) -> String {
     match first.as_rule() {
         Rule::identifier => first.as_str().to_owned(),
         Rule::string_literal => STRING_LITERAL_PARSER.parse(first.into_inner()),
+        Rule::raw_string_literal => {
+            let (content,) = first.into_inner().collect_tuple().unwrap();
+            assert_eq!(content.as_rule(), Rule::raw_string_content);
+            content.as_str().to_owned()
+        }
         _ => {
             panic!("unexpected symbol parse rule: {:?}", first.as_str());
         }
@@ -2839,6 +2846,13 @@ mod tests {
                 "foo bar".to_string()
             ))
         );
+        assert_eq!(
+            parse(r#"'foo bar'@'bar baz'"#),
+            Ok(RevsetExpression::remote_symbol(
+                "foo bar".to_string(),
+                "bar baz".to_string()
+            ))
+        );
         // Quoted "@" is not interpreted as a working copy or remote symbol
         assert_eq!(
             parse(r#""@""#),
@@ -2895,6 +2909,7 @@ mod tests {
         assert_eq!(parse("(foo)"), Ok(foo_symbol.clone()));
         // Parse a quoted symbol
         assert_eq!(parse("\"foo\""), Ok(foo_symbol.clone()));
+        assert_eq!(parse("'foo'"), Ok(foo_symbol.clone()));
         // Parse the "parents" operator
         assert_eq!(parse("foo-"), Ok(foo_symbol.parents()));
         // Parse the "children" operator
@@ -3070,12 +3085,13 @@ mod tests {
 
     #[test]
     fn test_parse_string_literal() {
+        let branches_expr =
+            |s: &str| RevsetExpression::branches(StringPattern::Substring(s.to_owned()));
+
         // "\<char>" escapes
         assert_eq!(
             parse(r#"branches("\t\r\n\"\\\0")"#),
-            Ok(RevsetExpression::branches(StringPattern::Substring(
-                "\t\r\n\"\\\0".to_owned()
-            )))
+            Ok(branches_expr("\t\r\n\"\\\0"))
         );
 
         // Invalid "\<char>" escape
@@ -3083,6 +3099,12 @@ mod tests {
             parse(r#"branches("\y")"#),
             Err(RevsetParseErrorKind::SyntaxError)
         );
+
+        // Single-quoted raw string
+        assert_eq!(parse(r#"branches('')"#), Ok(branches_expr("")));
+        assert_eq!(parse(r#"branches('a\n')"#), Ok(branches_expr(r"a\n")));
+        assert_eq!(parse(r#"branches('\')"#), Ok(branches_expr(r"\")));
+        assert_eq!(parse(r#"branches('"')"#), Ok(branches_expr(r#"""#)));
     }
 
     #[test]
@@ -3117,6 +3139,12 @@ mod tests {
                 "foo".to_owned()
             )))
         );
+        assert_eq!(
+            parse(r#"branches(exact:'\')"#),
+            Ok(RevsetExpression::branches(StringPattern::Exact(
+                r"\".to_owned()
+            )))
+        );
         assert_eq!(
             parse(r#"branches(bad:"foo")"#),
             Err(RevsetParseErrorKind::InvalidFunctionArguments {
@@ -3426,8 +3454,8 @@ mod tests {
 
         // String literal should not be substituted with alias.
         assert_eq!(
-            parse_with_aliases(r#"A|"A""#, [("A", "a")]).unwrap(),
-            parse("a|A").unwrap()
+            parse_with_aliases(r#"A|"A"|'A'"#, [("A", "a")]).unwrap(),
+            parse("a|A|A").unwrap()
         );
 
         // Alias can be substituted to string literal.