Type alias

schala-lang/language/src/parser.rs

@@ -15,18 +15,20 @@ use nom::sequence::{pair, delimited};
 use crate::ast::*;
 use crate::builtin::Builtin;
 
+type ParseResult<'a, T> = IResult<&'a str, T>;
 
-fn single_alphabetic_character(text: &str) -> IResult<&str, char> {
+
+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)
 }
 
-fn single_alphanumeric_character(text: &str) -> IResult<&str, char> {
+fn single_alphanumeric_character(text: &str) -> ParseResult<char> {
   let p = verify(take(1usize), |s: &str| s.chars().nth(0).map(|c| c.is_alphanumeric() || c == '_').unwrap_or(false));
   map(p, |s: &str| s.chars().nth(0).unwrap())(text)
 }
 
-fn identifier(text: &str) -> IResult<&str, Rc<String>> {
+fn identifier(text: &str) -> ParseResult<Rc<String>> {
   use nom::character::complete::char;
   map(alt((
     pair(char('_'), many1(single_alphanumeric_character)),
@@ -37,37 +39,37 @@ fn identifier(text: &str) -> IResult<&str, Rc<String>> {
 }
 
 const OPERATOR_CHARS: &'static str = "~`!@#$%^&*-+=<>?/|";
-fn parse_binop(input: &str) -> IResult<&str, BinOp> {
+fn parse_binop(text: &str) -> ParseResult<BinOp> {
-  let (rest, op): (_, Vec<char>) = many1(one_of(OPERATOR_CHARS))(input)?;
+  let (text, op): (_, Vec<char>) = many1(one_of(OPERATOR_CHARS))(text)?;
   let sigil: String = op.into_iter().collect();
-  Ok((rest, BinOp::from_sigil(&sigil)))
+  Ok((text, BinOp::from_sigil(&sigil)))
 }
 
-fn parse_bool_literal(input: &str) -> IResult<&str, ExpressionKind> {
+fn parse_bool_literal(text: &str) -> ParseResult<ExpressionKind> {
   let p = alt((
     value(true, tag("true")),
     value(false, tag("false"))
   ));
-  map(p, ExpressionKind::BoolLiteral)(input)
+  map(p, ExpressionKind::BoolLiteral)(text)
 }
 
-fn parse_number_literal(input: &str) -> IResult<&str, ExpressionKind> {
+fn parse_number_literal(text: &str) -> ParseResult<ExpressionKind> {
   let num_lit = many1(alt((
     map(one_of("1234567890"), |s: char| Some(s)),
     map(nom::character::complete::char('_'), |_| None)
   )));
 
-  let (rest, n) = map_res(num_lit,
+  let (text, n) = map_res(num_lit,
     |digits: Vec<Option<char>>| {
       let num_str: String = digits.into_iter().filter_map(|x| x).collect();
       u64::from_str_radix(&num_str, 10)
-    })(input)?;
+    })(text)?;
 
-  Ok((rest, ExpressionKind::NatLiteral(n)))
+  Ok((text, ExpressionKind::NatLiteral(n)))
 }
 
 
-fn parse_binary_literal(input: &str) -> IResult<&str, ExpressionKind> {
+fn parse_binary_literal(input: &str) -> ParseResult<ExpressionKind> {
   let (rest, _) = tag("0b")(input)?;
   let (rest, n): (&str, u64) = map_res(
     take_while(|c: char| c == '0' || c == '1'),
@@ -77,7 +79,7 @@ fn parse_binary_literal(input: &str) -> IResult<&str, ExpressionKind> {
   Ok((rest, expr))
 }
 
-fn parse_hex_literal(input: &str) -> IResult<&str, ExpressionKind> {
+fn parse_hex_literal(input: &str) -> ParseResult<ExpressionKind> {
   let (rest, _) = tag("0x")(input)?;
   let (rest, n): (&str, u64) = map_res(
     take_while(|c: char| c.is_digit(16)),
@@ -87,7 +89,7 @@ fn parse_hex_literal(input: &str) -> IResult<&str, ExpressionKind> {
   Ok((rest, expr))
 }
 
-fn parse_string_literal(text: &str) -> IResult<&str, ExpressionKind> {
+fn parse_string_literal(text: &str) -> ParseResult<ExpressionKind> {
   use nom::character::complete::char;
   let (text, string_output) = delimited(
     char('"'), take_until("\""), char('"')
@@ -96,7 +98,7 @@ fn parse_string_literal(text: &str) -> IResult<&str, ExpressionKind> {
   Ok((text, expr))
 }
 
-fn literal(input: &str) -> IResult<&str, ExpressionKind> {
+fn literal(input: &str) -> ParseResult<ExpressionKind> {
   alt((
     parse_string_literal,
     parse_hex_literal,
@@ -106,18 +108,18 @@ fn literal(input: &str) -> IResult<&str, ExpressionKind> {
   ))(input)
 }
 
-fn paren_expr(text: &str) -> IResult<&str, ExpressionKind> {
+fn paren_expr(text: &str) -> ParseResult<ExpressionKind> {
   use nom::character::complete::char;
   delimited(char('('), expression_kind, char(')'))(text)
 }
 
-fn prefix_op(input: &str) -> IResult<&str, PrefixOp> {
+fn prefix_op(input: &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)
 }
 
-fn identifier_expr(text: &str) -> IResult<&str, ExpressionKind> {
+fn identifier_expr(text: &str) -> ParseResult<ExpressionKind> {
   let (text, qualified_identifier) = map(
     qualified_identifier_list,
     |components| QualifiedName { id: ItemId::new(0), components }
@@ -127,11 +129,11 @@ fn identifier_expr(text: &str) -> IResult<&str, ExpressionKind> {
   Ok((text, exp.kind))
 }
 
-fn qualified_identifier_list(text: &str) -> IResult<&str, Vec<Rc<String>>> {
+fn qualified_identifier_list(text: &str) -> ParseResult<Vec<Rc<String>>> {
   separated_nonempty_list(tag("::"), identifier)(text)
 }
 
-fn primary_expr(text: &str) -> IResult<&str, ExpressionKind> {
+fn primary_expr(text: &str) -> ParseResult<ExpressionKind> {
   // primary := literal | paren_expr | if_expr | for_expr | while_expr | identifier_expr | lambda_expr | anonymous_struct | list_expr
 
   alt((
@@ -141,7 +143,7 @@ fn primary_expr(text: &str) -> IResult<&str, ExpressionKind> {
   ))(text)
 }
 
-fn invocation_argument(text: &str) -> IResult<&str, InvocationArgument> {
+fn invocation_argument(text: &str) -> ParseResult<InvocationArgument> {
   use nom::character::complete::char;
   alt((
     value(InvocationArgument::Ignored, pair(char('_'), alphanumeric0)),
@@ -151,7 +153,7 @@ fn invocation_argument(text: &str) -> IResult<&str, InvocationArgument> {
   ))(text)
 }
 
-fn call_expr(text: &str) -> IResult<&str, ExpressionKind> {
+fn call_expr(text: &str) -> ParseResult<ExpressionKind> {
   use nom::character::complete::char;
   let (text, expr) = primary_expr(text)?;
   let (text, call_part) = opt(
@@ -166,7 +168,7 @@ fn call_expr(text: &str) -> IResult<&str, ExpressionKind> {
   Ok((text, output))
 }
 
-fn prefix_expr(text: &str) -> IResult<&str, ExpressionKind> {
+fn prefix_expr(text: &str) -> ParseResult<ExpressionKind> {
   let (text, pfx) = delimited(space0, opt(prefix_op), space0)(text)?;
   let (text, result) = call_expr(text)?;
   match pfx {
@@ -179,7 +181,7 @@ fn prefix_expr(text: &str) -> IResult<&str, ExpressionKind> {
 }
 
 // this implements Pratt parsing, see http://journal.stuffwithstuff.com/2011/03/19/pratt-parsers-expression-parsing-made-easy/
-fn precedence_expr(input: &str, precedence: i32) -> IResult<&str, ExpressionKind>  {
+fn precedence_expr(input: &str, precedence: i32) -> ParseResult<ExpressionKind> {
   let (mut outer_rest, mut lhs) = prefix_expr(input)?;
   loop {
     let (rest, _) = space0(outer_rest)?;
@@ -203,7 +205,7 @@ fn precedence_expr(input: &str, precedence: i32) -> IResult<&str, ExpressionKind
   Ok((outer_rest, lhs))
 }
 
-fn expression_kind(input: &str) -> IResult<&str, ExpressionKind> {
+fn expression_kind(input: &str) -> ParseResult<ExpressionKind> {
   precedence_expr(input, BinOp::min_precedence())
 }