From aa417bd172ff4e3bb4020bdd7f65da42c5ec7c14 Mon Sep 17 00:00:00 2001 From: Caleb Jones Date: Sat, 24 Dec 2016 19:01:27 -0500 Subject: [PATCH] Add parsing for symbols --- src/lib.rs | 95 ++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 68 insertions(+), 27 deletions(-) diff --git a/src/lib.rs b/src/lib.rs index 2d83e75..85c3594 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -10,7 +10,7 @@ use std::borrow::Cow; /// purposes. #[derive(Debug, PartialEq, Clone, PartialOrd)] pub enum Sexp<'a, Loc=ByteSpan> where Loc: Span { - /// A value representing a symbol. A symbol is an atomic unit + /// A value representing a symbol. Sym(Cow<'a, str>, Loc), /// A value representing a string literal. Str(Cow<'a, str>, Loc), @@ -19,10 +19,10 @@ pub enum Sexp<'a, Loc=ByteSpan> where Loc: Span { /// A value representing an integer. Any number containing no decimal point /// will be parsed as an `Int`. Int(i64, Loc), - /// A value representing a float. Any number containing a decimal point will - /// be parsed as a `Float`. + /// A value representing a floating point number. Any number containing a + /// decimal point will be parsed as a `Float`. Float(f64, Loc), - /// A list of subexpressions + /// A list of subexpressions. List(Vec>, Loc), } @@ -77,7 +77,8 @@ use ParseResult::*; pub enum ParseError where Loc: Span { /// We can't explain how the parsing failed. UnexpectedEof, - Number(Option>, Loc), + Symbol(Box, Loc), + Number(Box, Loc), Unexpected(char, Loc::Begin), Unimplemented, } @@ -133,7 +134,7 @@ pub fn parse_number(input: &str, start_loc: usize) -> ParseResult ParseResult { return Error(ParseError::Number( - Some(Box::new(ParseError::Unexpected(c, 0))), + Box::new(ParseError::Unexpected(c, 0)), (0, c.len_utf8()).offset(start_loc))); } None => return Error(ParseError::Number( - Some(Box::new(ParseError::UnexpectedEof)), + Box::new(ParseError::UnexpectedEof), (0, 0).offset(start_loc))), _ => (), } @@ -170,7 +171,7 @@ pub fn parse_number(input: &str, start_loc: usize) -> ParseResult ParseResult ParseResult ParseResult { + let end_of_white = if let Some(pos) = input.find(|c: char| !c.is_whitespace()) { + pos + } else { + return Error(ParseError::Symbol( + Box::new(ParseError::UnexpectedEof), + (input.len(), input.len()).offset(start_loc))); + }; + + let input = &input[end_of_white..]; + let start_loc = start_loc + end_of_white; + + match input.chars().next() { + Some(c@'#') | Some(c@':') | Some(c@'0'...'9') => + return Error(ParseError::Symbol( + Box::new(ParseError::Unexpected(c, start_loc)), + (0, 0).offset(start_loc))), + Some(c) if c.is_delimiter() => + return Error(ParseError::Symbol( + Box::new(ParseError::Unexpected(c, start_loc)), + (0, 0).offset(start_loc))), + Some(_) => (), + None => unreachable!(), + } + + for (i, c) in input.char_indices() { + if c.is_delimiter() { + return Done(&input[i..], + Sexp::Sym(input[..i].into(), (0, i).offset(start_loc))); + } + } + + Done(&input[input.len()..], + Sexp::Sym(input.into(), (0, input.len()).offset(start_loc))) +} + // Tests /////////////////////////////////////////////////////////////////////// @@ -222,27 +259,31 @@ mod test { assert_eq!(parse_number("1()", 0), Done("()", Sexp::Int(1, (0, 1)))); assert_eq!(parse_number("3.6()", 0), Done("()", Sexp::Float(3.6, (0, 3)))); - assert_eq!(parse_number("", 0), Error(ParseError::Number(Some(Box::new(ParseError::UnexpectedEof)), (0, 0)))); - assert_eq!(parse_number("123a", 0), Error(ParseError::Number(Some(Box::new(ParseError::Unexpected('a', 3))), (3, 3)))); - assert_eq!(parse_number("66.6+", 0), Error(ParseError::Number(Some(Box::new(ParseError::Unexpected('+', 4))), (4, 4)))); + assert_eq!(parse_number("", 0), Error(ParseError::Number(Box::new(ParseError::UnexpectedEof), (0, 0)))); + assert_eq!(parse_number("123a", 0), Error(ParseError::Number(Box::new(ParseError::Unexpected('a', 3)), (3, 3)))); + assert_eq!(parse_number("66.6+", 0), Error(ParseError::Number(Box::new(ParseError::Unexpected('+', 4)), (4, 4)))); + } + + #[test] + fn test_parse_ident() { + assert_eq!(parse_symbol("+", 0), Done("", Sexp::Sym("+".into(), (0, 1)))); + assert_eq!(parse_symbol(" nil?", 0), Done("", Sexp::Sym("nil?".into(), (1, 5)))); + assert_eq!(parse_symbol(" ->socket", 0), Done("", Sexp::Sym("->socket".into(), (1, 9)))); + assert_eq!(parse_symbol("fib(", 0), Done("(", Sexp::Sym("fib".into(), (0, 3)))); + assert_eq!(parse_symbol("foo2", 0), Done("", Sexp::Sym("foo2".into(), (0, 4)))); + + // We reserve #foo for the implementation to do as it wishes + assert_eq!(parse_symbol("#hi", 0), Error(ParseError::Symbol(Box::new(ParseError::Unexpected('#', 0)), (0, 0)))); + // We reserve :foo for keywords + assert_eq!(parse_symbol(":hi", 0), Error(ParseError::Symbol(Box::new(ParseError::Unexpected(':', 0)), (0, 0)))); + + assert_eq!(parse_symbol("", 0), Error(ParseError::Symbol(Box::new(ParseError::UnexpectedEof), (0, 0)))); + assert_eq!(parse_symbol("0", 0), Error(ParseError::Symbol(Box::new(ParseError::Unexpected('0', 0)), (0, 0)))); + assert_eq!(parse_symbol("()", 0), Error(ParseError::Symbol(Box::new(ParseError::Unexpected('(', 0)), (0, 0)))); } } // #[cfg(test)] -// #[test] -// fn test_parse_ident() { -// assert_eq!(symbol("+"), IResult::Done("", Sexp::Sym("+".into()))); -// assert_eq!(symbol(" nil?"), IResult::Done("", Sexp::Sym("nil?".into()))); -// assert_eq!(symbol(" ->socket"), IResult::Done("", Sexp::Sym("->socket".into()))); -// assert_eq!(symbol("fib("), IResult::Done("(", Sexp::Sym("fib".into()))); - -// // We reserve #foo for the implementation to do as it wishes -// assert!(symbol("#hi").is_err()); - -// assert!(symbol("0").is_err()); -// assert!(symbol("()").is_err()); -// assert!(symbol("").is_incomplete()); -// } // #[cfg(test)] // #[test] -- 2.43.2