Some wording changes; added ws combinator

schala-lang/language/src/parser.rs

@@ -8,7 +8,7 @@ use nom::character::complete::{one_of, space0, alphanumeric0};
 use nom::bytes::complete::{tag, take, take_while, take_while1, take_until};
 use nom::combinator::{cut, map, map_res, value, opt, verify};
 use nom::multi::{separated_list, separated_nonempty_list, many1, many0};
-use nom::error::{context, VerboseError};
+use nom::error::{context, ParseError, VerboseError};
 use nom::branch::alt;
 use nom::sequence::{pair, delimited, preceded};
 
@@ -18,6 +18,16 @@ use crate::builtin::Builtin;
 type ParseResult<'a, T> = IResult<&'a str, T, VerboseError<&'a str>>;
 
 
+pub fn ws<I, O, E: ParseError<I>, F>(parser: F) -> impl Fn(I) -> IResult<I, O, E>
+where
+    I: nom::InputTakeAtPosition,
+    <I as nom::InputTakeAtPosition>::Item: nom::AsChar + Clone,
+    F: Fn(I) -> IResult<I, O, E>,
+    {
+      delimited(space0, parser, space0)
+    }
+
+
 fn single_alphabetic_character(text: &str) -> ParseResult<char> {
   let p = verify(take(1usize), |s: &str| s.chars().nth(0).map(|c| c.is_alphabetic()).unwrap_or(false));
   map(p, |s: &str| s.chars().nth(0).unwrap())(text)
@@ -69,20 +79,20 @@ fn number_literal(text: &str) -> ParseResult<ExpressionKind> {
 }
 
 
-fn binary_literal(input: &str) -> ParseResult<ExpressionKind> {
+fn binary_literal(text: &str) -> ParseResult<ExpressionKind> {
   let p = preceded(tag("0b"), cut(take_while1(|c: char| c == '0' || c == '1')));
   let (rest, n): (&str, u64) = map_res(
     p, |hex_str: &str| u64::from_str_radix(hex_str, 2)
-  )(input)?;
+  )(text)?;
   let expr = ExpressionKind::NatLiteral(n);
   Ok((rest, expr))
 }
 
-fn hex_literal(input: &str) -> ParseResult<ExpressionKind> {
+fn hex_literal(text: &str) -> ParseResult<ExpressionKind> {
   let p = preceded(tag("0x"), cut(take_while1(|c: char| c.is_digit(16))));
   let (rest, n): (&str, u64) = map_res(
     p, |hex_str: &str| u64::from_str_radix(hex_str, 16)
-  )(input)?;
+  )(text)?;
   let expr = ExpressionKind::NatLiteral(n);
   Ok((rest, expr))
 }
@@ -96,14 +106,14 @@ fn string_literal(text: &str) -> ParseResult<ExpressionKind> {
   Ok((text, expr))
 }
 
-fn literal(input: &str) -> ParseResult<ExpressionKind> {
+fn literal(text: &str) -> ParseResult<ExpressionKind> {
   alt((
     string_literal,
     hex_literal,
     binary_literal,
     number_literal,
     bool_literal,
-  ))(input)
+  ))(text)
 }
 
 fn paren_expr(text: &str) -> ParseResult<ExpressionKind> {
@@ -111,10 +121,10 @@ fn paren_expr(text: &str) -> ParseResult<ExpressionKind> {
   context("Paren expression", delimited(char('('), expression_kind, char(')')))(text)
 }
 
-fn prefix_op(input: &str) -> ParseResult<PrefixOp> {
+fn prefix_op(text: &str) -> ParseResult<PrefixOp> {
   use nom::character::complete::char;
   let p = alt((char('+'), char('-'), char('!')));
-  map(p, |sigil| PrefixOp::from_str(&sigil.to_string()).unwrap())(input)
+  map(p, |sigil| PrefixOp::from_str(&sigil.to_string()).unwrap())(text)
 }
 
 fn identifier_expr(text: &str) -> ParseResult<ExpressionKind> {
@@ -167,7 +177,7 @@ fn call_expr(text: &str) -> ParseResult<ExpressionKind> {
 }
 
 fn prefix_expr(text: &str) -> ParseResult<ExpressionKind> {
-  let (text, pfx) = delimited(space0, opt(prefix_op), space0)(text)?;
+  let (text, pfx) = ws(opt(prefix_op))(text)?;
   let (text, result) = call_expr(text)?;
   match pfx {
     None => Ok((text, result)),
@@ -209,9 +219,20 @@ fn precedence_expr(text: &str) -> ParseResult<ExpressionKind> {
 }
 
 fn expression_kind(text: &str) -> ParseResult<ExpressionKind> {
-  precedence_expr(text)
+  context("Expression kind", precedence_expr)(text)
 }
 
+/*
+fn type_anno(text: &str) -> ParseResult<TypeIdentifier> {
+
+}
+
+fn expression(text: &str) -> ParseResult<Expression> {
+  let (rest, (kind, type_anno)) = pair(expression_kind, type_anno)(text)?;
+  Ok((rest, Expression::with_anno(ItemId::new(0), kind, type_anno)))
+}
+*/
+
 pub fn perform_parsing(input: &str) -> Result<String, String> {
   let output = match expression_kind(input) {
     Ok((rest, ast)) => format!("{:?} (rest: {})", ast, rest),