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-rw-r--r--helix-lsp/src/snippet.rs367
1 files changed, 367 insertions, 0 deletions
diff --git a/helix-lsp/src/snippet.rs b/helix-lsp/src/snippet.rs
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+++ b/helix-lsp/src/snippet.rs
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+use anyhow::{anyhow, Result};
+
+use crate::{util::lsp_pos_to_pos, OffsetEncoding};
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum CaseChange {
+ Upcase,
+ Downcase,
+ Capitalize,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum FormatItem<'a> {
+ Text(&'a str),
+ Capture(usize),
+ CaseChange(usize, CaseChange),
+ Conditional(usize, Option<&'a str>, Option<&'a str>),
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Regex<'a> {
+ value: &'a str,
+ replacement: Vec<FormatItem<'a>>,
+ options: Option<&'a str>,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum SnippetElement<'a> {
+ Tabstop {
+ tabstop: usize,
+ },
+ Placeholder {
+ tabstop: usize,
+ value: Box<SnippetElement<'a>>,
+ },
+ Choice {
+ tabstop: usize,
+ choices: Vec<&'a str>,
+ },
+ Variable {
+ name: &'a str,
+ default: Option<&'a str>,
+ regex: Option<Regex<'a>>,
+ },
+ Text(&'a str),
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Snippet<'a> {
+ elements: Vec<SnippetElement<'a>>,
+}
+
+pub fn parse<'a>(s: &'a str) -> Result<Snippet<'a>> {
+ parser::parse(s).map_err(|rest| anyhow!("Failed to parse snippet. Remaining input: {}", rest))
+}
+
+mod parser {
+ use helix_core::regex;
+ use once_cell::sync::Lazy;
+
+ use helix_parsec::*;
+
+ use super::{CaseChange, FormatItem, Regex, Snippet, SnippetElement};
+
+ /*
+ https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#snippet_syntax
+
+ any ::= tabstop | placeholder | choice | variable | text
+ tabstop ::= '$' int | '${' int '}'
+ placeholder ::= '${' int ':' any '}'
+ choice ::= '${' int '|' text (',' text)* '|}'
+ variable ::= '$' var | '${' var }'
+ | '${' var ':' any '}'
+ | '${' var '/' regex '/' (format | text)+ '/' options '}'
+ format ::= '$' int | '${' int '}'
+ | '${' int ':' '/upcase' | '/downcase' | '/capitalize' '}'
+ | '${' int ':+' if '}'
+ | '${' int ':?' if ':' else '}'
+ | '${' int ':-' else '}' | '${' int ':' else '}'
+ regex ::= Regular Expression value (ctor-string)
+ options ::= Regular Expression option (ctor-options)
+ var ::= [_a-zA-Z] [_a-zA-Z0-9]*
+ int ::= [0-9]+
+ text ::= .*
+ if ::= text
+ else ::= text
+ */
+
+ static DIGIT: Lazy<regex::Regex> = Lazy::new(|| regex::Regex::new(r"^[0-9]+").unwrap());
+ static VARIABLE: Lazy<regex::Regex> =
+ Lazy::new(|| regex::Regex::new(r"^[_a-zA-Z][_a-zA-Z0-9]*").unwrap());
+ static TEXT: Lazy<regex::Regex> = Lazy::new(|| regex::Regex::new(r"^[^\$]+").unwrap());
+
+ fn var<'a>() -> impl Parser<'a, Output = &'a str> {
+ pattern(&VARIABLE)
+ }
+
+ fn digit<'a>() -> impl Parser<'a, Output = usize> {
+ filter_map(pattern(&DIGIT), |s| s.parse().ok())
+ }
+
+ fn case_change<'a>() -> impl Parser<'a, Output = CaseChange> {
+ use CaseChange::*;
+
+ choice!(
+ map("upcase", |_| Upcase),
+ map("downcase", |_| Downcase),
+ map("capitalize", |_| Capitalize),
+ )
+ }
+
+ fn format<'a>() -> impl Parser<'a, Output = FormatItem<'a>> {
+ use FormatItem::*;
+
+ choice!(
+ // '$' int
+ map(right("$", digit()), Capture),
+ // '${' int '}'
+ map(seq!("${", digit(), "}"), |seq| Capture(seq.1)),
+ // '${' int ':' '/upcase' | '/downcase' | '/capitalize' '}'
+ map(seq!("${", digit(), ":/", case_change(), "}"), |seq| {
+ CaseChange(seq.1, seq.3)
+ }),
+ // '${' int ':+' if '}'
+ map(
+ seq!("${", digit(), ":+", take_until(|c| c == '}'), "}"),
+ |seq| { Conditional(seq.1, Some(seq.3), None) }
+ ),
+ // '${' int ':?' if ':' else '}'
+ map(
+ seq!(
+ "${",
+ digit(),
+ ":?",
+ take_until(|c| c == ':'),
+ ":",
+ take_until(|c| c == '}'),
+ "}"
+ ),
+ |seq| { Conditional(seq.1, Some(seq.3), Some(seq.5)) }
+ ),
+ // '${' int ':-' else '}' | '${' int ':' else '}'
+ map(
+ seq!(
+ "${",
+ digit(),
+ ":",
+ optional("-"),
+ take_until(|c| c == '}'),
+ "}"
+ ),
+ |seq| { Conditional(seq.1, None, Some(seq.4)) }
+ ),
+ // Any text
+ map(pattern(&TEXT), Text),
+ )
+ }
+
+ fn regex<'a>() -> impl Parser<'a, Output = Regex<'a>> {
+ let replacement = reparse_as(take_until(|c| c == '/'), one_or_more(format()));
+
+ map(
+ seq!(
+ "/",
+ take_until(|c| c == '/'),
+ "/",
+ replacement,
+ "/",
+ optional(take_until(|c| c == '}')),
+ ),
+ |(_, value, _, replacement, _, options)| Regex {
+ value,
+ replacement,
+ options,
+ },
+ )
+ }
+
+ fn tabstop<'a>() -> impl Parser<'a, Output = SnippetElement<'a>> {
+ map(
+ or(
+ right("$", digit()),
+ map(seq!("${", digit(), "}"), |values| values.1),
+ ),
+ |digit| SnippetElement::Tabstop { tabstop: digit },
+ )
+ }
+
+ fn placeholder<'a>() -> impl Parser<'a, Output = SnippetElement<'a>> {
+ // TODO: why doesn't parse_as work?
+ // let value = reparse_as(take_until(|c| c == '}'), anything());
+ let value = filter_map(take_until(|c| c == '}'), |s| {
+ anything().parse(s).map(|parse_result| parse_result.1).ok()
+ });
+
+ map(seq!("${", digit(), ":", value, "}"), |seq| {
+ SnippetElement::Placeholder {
+ tabstop: seq.1,
+ value: Box::new(seq.3),
+ }
+ })
+ }
+
+ fn choice<'a>() -> impl Parser<'a, Output = SnippetElement<'a>> {
+ map(
+ seq!(
+ "${",
+ digit(),
+ "|",
+ sep(take_until(|c| c == ',' || c == '|'), ","),
+ "|}",
+ ),
+ |seq| SnippetElement::Choice {
+ tabstop: seq.1,
+ choices: seq.3,
+ },
+ )
+ }
+
+ fn variable<'a>() -> impl Parser<'a, Output = SnippetElement<'a>> {
+ choice!(
+ // $var
+ map(right("$", var()), |name| SnippetElement::Variable {
+ name,
+ default: None,
+ regex: None,
+ }),
+ // ${var:default}
+ map(
+ seq!("${", var(), ":", take_until(|c| c == '}'), "}",),
+ |values| SnippetElement::Variable {
+ name: values.1,
+ default: Some(values.3),
+ regex: None,
+ }
+ ),
+ // ${var/value/format/options}
+ map(seq!("${", var(), regex(), "}"), |values| {
+ SnippetElement::Variable {
+ name: values.1,
+ default: None,
+ regex: Some(values.2),
+ }
+ }),
+ )
+ }
+
+ fn text<'a>() -> impl Parser<'a, Output = SnippetElement<'a>> {
+ map(pattern(&TEXT), SnippetElement::Text)
+ }
+
+ fn anything<'a>() -> impl Parser<'a, Output = SnippetElement<'a>> {
+ choice!(tabstop(), placeholder(), choice(), variable(), text())
+ }
+
+ fn snippet<'a>() -> impl Parser<'a, Output = Snippet<'a>> {
+ map(one_or_more(anything()), |parts| Snippet { elements: parts })
+ }
+
+ pub fn parse(s: &str) -> Result<Snippet, &str> {
+ snippet().parse(s).map(|(_input, elements)| elements)
+ }
+
+ #[cfg(test)]
+ mod test {
+ use super::SnippetElement::*;
+ use super::*;
+
+ #[test]
+ fn empty_string_is_error() {
+ assert_eq!(Err(""), parse(""));
+ }
+
+ #[test]
+ fn parse_placeholders_in_function_call() {
+ assert_eq!(
+ Ok(Snippet {
+ elements: vec![
+ Text("match("),
+ Placeholder {
+ tabstop: 1,
+ value: Box::new(Text("Arg1")),
+ },
+ Text(")")
+ ]
+ }),
+ parse("match(${1:Arg1})")
+ )
+ }
+
+ #[test]
+ fn parse_placeholders_in_statement() {
+ assert_eq!(
+ Ok(Snippet {
+ elements: vec![
+ Text("local "),
+ Placeholder {
+ tabstop: 1,
+ value: Box::new(Text("var")),
+ },
+ Text(" = "),
+ Placeholder {
+ tabstop: 1,
+ value: Box::new(Text("value")),
+ },
+ ]
+ }),
+ parse("local ${1:var} = ${1:value}")
+ )
+ }
+
+ #[test]
+ fn parse_all() {
+ assert_eq!(
+ Ok(Snippet {
+ elements: vec![
+ Text("hello "),
+ Tabstop { tabstop: 1 },
+ Tabstop { tabstop: 2 },
+ Text(" "),
+ Choice {
+ tabstop: 1,
+ choices: vec!["one", "two", "three"]
+ },
+ Text(" "),
+ Variable {
+ name: "name",
+ default: Some("foo"),
+ regex: None
+ },
+ Text(" "),
+ Variable {
+ name: "var",
+ default: None,
+ regex: None
+ },
+ Text(" "),
+ Variable {
+ name: "TM",
+ default: None,
+ regex: None
+ },
+ ]
+ }),
+ parse("hello $1${2} ${1|one,two,three|} ${name:foo} $var $TM")
+ );
+ }
+
+ #[test]
+ fn regex_capture_replace() {
+ assert_eq!(
+ Ok(Snippet {
+ elements: vec![Variable {
+ name: "TM_FILENAME",
+ default: None,
+ regex: Some(Regex {
+ value: "(.*).+$",
+ replacement: vec![FormatItem::Capture(1)],
+ options: None,
+ }),
+ }]
+ }),
+ parse("${TM_FILENAME/(.*).+$/$1/}")
+ );
+ }
+ }
+}