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Handle things separated by things differently

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I noticed that programs like '{} would parse correctly while '{ } would
expect an inner element. This was because the leading space was actually
part of the element parser, which is a violation of the (as of yet
unspoken) rule that parsers should not parse surrounding whitespace.

Because whitespace whas treated differently from everywhere else and
because this implementation was wrong, I decided to reimplement it,
abstracting the concept of things separated by other things with
optional trailing things. I did this in such a way that surrounding
whitespace is not touched.
This commit is contained in:
Joscha 2022-11-20 20:25:39 +01:00
parent 407786b98c
commit b009a9c4ec
10 changed files with 116 additions and 77 deletions
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21
src/parser/program.rs
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@ -4,7 +4,7 @@ use chumsky::prelude::*;
use crate::ast::{Expr, Program, Space, TableLitElem};
use super::basic::EParser;
use super::basic::{separated_by, EParser};
pub fn program(
space: EParser<Space>,
@ -17,20 +17,19 @@ pub fn program(
.then(space.clone())
.map_with_span(|((s0, expr), s1), span| Program::Expr { s0, expr, s1, span });
let elem = space
.clone()
.then(table_lit_elem)
.then(space.clone())
.map(|((s0, elem), s1)| (s0, elem, s1));
let trailing_comma = just(',').ignore_then(space.clone()).or_not();
let separator = space.clone().then_ignore(just(',')).then(space.clone());
let trailing_separator = space.clone().then_ignore(just(','));
let module = space
.clone()
.then_ignore(text::keyword("module"))
.then(elem.separated_by(just(',')))
.then(trailing_comma)
.map_with_span(|((s0, elems), trailing_comma), span| Program::Module {
.then(space.clone())
.then(separated_by(table_lit_elem, separator, trailing_separator))
.then(space.clone())
.map_with_span(|(((s0, s1), elems), s2), span| Program::Module {
s0,
s1,
elems,
trailing_comma,
s2,
span,
});