initial commit

Author: psteinroe

.gitignore

@@ -12,3 +12,8 @@ Cargo.lock
 
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
+
+
+# Added by cargo
+
+/target

Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "postgres_lsp"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+pg_query = "0.7"
+logos = "0.13.0"

src/example.sql

@@ -0,0 +1,12 @@
+select * from contact where id = '123';
+
+-- test comment
+
+select wrong statement;
+
+select id,username from contact
+
+select id,name
+from contact -- test inline comment
+where id = '123';
+

src/main.rs

@@ -0,0 +1,95 @@
+use logos::Logos;
+use std::fs;
+
+#[derive(Logos, Debug, PartialEq)]
+#[logos(skip r"[ \t\f]+")] // Ignore this regex pattern between tokens
+enum Token {
+ #[regex("[a-zA-Z0-9_]+[^;]*;"gm)]
+ Expr,
+ #[regex("\n+"gm)]
+ Newline,
+ #[regex("/\\*[^*]*\\*+(?:[^/*][^*]*\\*+)*/|--[^\n]*"g)]
+ Comment,
+}
+
+fn main() {
+ let source = fs::read_to_string("./src/example.sql").unwrap();
+ let mut lex = Token::lexer(&source);
+
+ println!("{:?}", source);
+
+ // https://github.com/domenicquirl/cstree
+ // https://ericlippert.com/2012/06/08/red-green-trees/
+ //
+ // So, for example, to parse a struct definition the parser first "enters" the struct definition node, then parses the struct keyword and type name, then parses each field, and finally "finishes" parsing the struct node.
+ //
+ // 1. lexer: parse string into tokens. cstree will allow us to just move forward until next
+ // statement. also, for comments, we should be able to store them separately since we are
+ // just walking over the source code. tokens should be expr, whitespace, newlines, comments
+ // and eof. does not work because lexer is "dumb". Token != SyntaxKind, so maybe we do not
+ // need a real lexer.
+ // 2. parser: parse tokens into cst with cstree. nodes are not typed, and we should be able to
+ // use pg_query to parse string, and turn that into SyntaxKind tokens.
+ //
+ //
+ // Notes:
+ // - maybe we do not real a lexer to parse into statements. we can just use simple string
+ // operations? or maybe lexer but with metadata on tokens because normally a token
+ // translates into a constant which is not what we want. instead, we want a token Expr to
+ // hold the expression string.
+
+ // problem: comments
+ // general problem: declarative parsing by token will, based on initial research, not work well because we have tokens
+ // within tokens (comment can be within a sql query)
+ // let parser = any::<_, extra::Err<Simple<char>>>()
+ // .and_is(just(';').not())
+ // .repeated()
+ // .collect::<String>()
+ // .padded()
+ // .separated_by(just(';'))
+ // .collect::<Vec<String>>();
+ //
+ // let comment = just("--")
+ // .then(
+ // any::<_, extra::Err<Simple<char>>>()
+ // .and_is(just('\n').not())
+ // .repeated(),
+ // )
+ // .padded();
+ //
+ // let comments = comment.parse(source.as_str());
+ // let result = parser.parse(source.as_str());
+ //
+ // println!("{:?}", source);
+ // println!("{:?}", result);
+ // println!("{:?}", comments);
+ //
+ // let pg_query_result = pg_query::parse("SELECT * FROM contacts").unwrap();
+ //
+ // println!("{:?}", pg_query_result.protobuf.nodes());
+}
+
+#[test]
+fn test_lexer() {
+ let input = "select * from contact where id = '123';\n\n-- test comment\n\nselect wrong statement;\n\nselect id,username from contact\n\nselect id,name\nfrom contact -- test inline comment\nwhere id = '123';\n\n";
+
+ let mut lex = Token::lexer(&input);
+
+ assert_eq!(lex.next(), Some(Ok(Token::Expr)));
+ assert_eq!(lex.slice(), "select * from contact where id = '123';");
+
+ assert_eq!(lex.next(), Some(Ok(Token::Newline)));
+
+ assert_eq!(lex.next(), Some(Ok(Token::Comment)));
+ assert_eq!(lex.slice(), "-- test comment");
+
+ assert_eq!(lex.next(), Some(Ok(Token::Newline)));
+
+ assert_eq!(lex.next(), Some(Ok(Token::Expr)));
+ assert_eq!(lex.slice(), "select wrong statement;");
+
+ assert_eq!(lex.next(), Some(Ok(Token::Newline)));
+
+ assert_eq!(lex.next(), Some(Ok(Token::Expr)));
+ assert_eq!(lex.slice(), "select id,username from contact\n\nselect id,name\nfrom contact -- test inline comment\nwhere id = '123';");
+}