From 76801174ef79f0edce88c932d541e6bfdfe808ed Mon Sep 17 00:00:00 2001 From: Caleb Jones Date: Sat, 24 Dec 2016 21:42:08 -0500 Subject: [PATCH] Refactor consuming whitespace into a macro --- src/lib.rs | 75 +++++++++++++++++------------------------------------- 1 file changed, 24 insertions(+), 51 deletions(-) diff --git a/src/lib.rs b/src/lib.rs index 11dfc18..84dc7e8 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -77,6 +77,7 @@ use ParseResult::*; pub enum ParseError where Loc: Span { /// We can't explain how the parsing failed. UnexpectedEof, + Sexp(Box, Loc), Char(Box, Loc), String(Box, Loc), Symbol(Box, Loc), @@ -126,17 +127,20 @@ impl IsDelimeter for char { // Parsers ///////////////////////////////////////////////////////////////////// -pub fn parse_sexp(input: &str, start_loc: usize) -> ParseResult { - let end_of_white = if let Some(pos) = input.find(|c: char| !c.is_whitespace()) { - pos - } else { - return Error(ParseError::Number( - Box::new(ParseError::UnexpectedEof), - (input.len(), input.len()).offset(start_loc))); - }; +macro_rules! consume_whitespace { + ($input:expr, $start_loc:expr, $ErrorFn:expr) => { + if let Some(pos) = $input.find(|c: char| !c.is_whitespace()) { + (&$input[pos..], $start_loc + pos) + } else { + return Error($ErrorFn( + 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; +pub fn parse_sexp(input: &str, start_loc: usize) -> ParseResult { + let (input, start_loc) = consume_whitespace!(input, start_loc, ParseError::Sexp); match input.chars().next() { Some('0'...'9') => parse_number(input, start_loc), @@ -149,17 +153,7 @@ pub fn parse_sexp(input: &str, start_loc: usize) -> ParseResult ParseResult { - // Consume all the whitespace at the beginning of the string - let end_of_white = if let Some(pos) = input.find(|c: char| !c.is_whitespace()) { - pos - } else { - return Error(ParseError::Number( - 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; + let (input, start_loc) = consume_whitespace!(input, start_loc, ParseError::Number); match input.chars().next() { Some(c) if !c.is_digit(10) => { @@ -225,16 +219,7 @@ pub fn parse_number(input: &str, start_loc: usize) -> 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; + let (input, start_loc) = consume_whitespace!(input, start_loc, ParseError::Symbol); match input.chars().next() { Some(c@'#') | Some(c@':') | Some(c@'0'...'9') => @@ -261,16 +246,7 @@ pub fn parse_symbol(input: &str, start_loc: usize) -> ParseResult ParseResult { - let end_of_white = if let Some(pos) = input.find(|c: char| !c.is_whitespace()) { - pos - } else { - return Error(ParseError::String( - 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; + let (input, start_loc) = consume_whitespace!(input, start_loc, ParseError::String); match input.chars().next() { Some('"') => (), @@ -294,16 +270,7 @@ pub fn parse_string(input: &str, start_loc: usize) -> ParseResult ParseResult { - let end_of_white = if let Some(pos) = input.find(|c: char| !c.is_whitespace()) { - pos - } else { - return Error(ParseError::String( - 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; + let (input, start_loc) = consume_whitespace!(input, start_loc, ParseError::Char); match input.chars().nth(0) { Some('#') => (), @@ -354,6 +321,8 @@ mod test { assert_eq!(parse_sexp(" a", 0), Done("", Sexp::Sym("a".into(), (1, 2)))); assert_eq!(parse_sexp("#\\c", 0), Done("", Sexp::Char('c', (0, 3)))); assert_eq!(parse_sexp(r#""hi""#, 0), Done("", Sexp::Str("hi".into(), (0, 4)))); + + assert_eq!(parse_sexp("", 0), Error(ParseError::Sexp(Box::new(ParseError::UnexpectedEof), (0, 0)))); } #[test] @@ -397,6 +366,8 @@ mod test { assert_eq!(parse_string(r#" "this is a nice string with 0123 things in it""#, 0), Done("", Sexp::Str("this is a nice string\nwith 0123 things in it".into(), (2, 48)))); + + assert_eq!(parse_string("", 0), Error(ParseError::String(Box::new(ParseError::UnexpectedEof), (0, 0)))); assert_eq!(parse_string(r#""hi"#, 0), Error(ParseError::String(Box::new(ParseError::UnexpectedEof), (0, 3)))); } @@ -406,7 +377,9 @@ with 0123 things in it""#, 0), assert_eq!(parse_character(r#"#\ "#, 0), Done("", Sexp::Char(' ', (0, 3)))); assert_eq!(parse_character(r#" #\\"#, 0), Done("", Sexp::Char('\\', (2, 5)))); + assert_eq!(parse_character("", 0), Error(ParseError::Char(Box::new(ParseError::UnexpectedEof), (0, 0)))); assert_eq!(parse_character("#", 0), Error(ParseError::Char(Box::new(ParseError::UnexpectedEof), (1, 1)))); + assert_eq!(parse_character("#\\", 0), Error(ParseError::Char(Box::new(ParseError::UnexpectedEof), (2, 2)))); assert_eq!(parse_character("a", 0), Error(ParseError::Char(Box::new(ParseError::Unexpected('a', 0)), (0, 0)))); } } -- 2.47.0