grass/src/function.rs

105 lines
3.3 KiB
Rust

use std::iter::Peekable;
use crate::args::{eat_func_args, CallArgs, FuncArgs};
use crate::atrule::AtRule;
use crate::common::Symbol;
use crate::error::SassResult;
use crate::scope::Scope;
use crate::selector::Selector;
use crate::utils::devour_whitespace;
use crate::value::Value;
use crate::{Token, TokenKind};
#[derive(Debug, Clone)]
pub(crate) struct Function {
scope: Scope,
args: FuncArgs,
body: Vec<AtRule>,
}
impl Function {
pub fn new(scope: Scope, args: FuncArgs, body: Vec<AtRule>) -> Self {
Function { scope, args, body }
}
pub fn decl_from_tokens<I: Iterator<Item = Token>>(
toks: &mut Peekable<I>,
mut scope: Scope,
super_selector: &Selector,
) -> SassResult<(String, Function)> {
let Token { kind, .. } = toks
.next()
.expect("this must exist because we have already peeked");
devour_whitespace(toks);
let name = match kind {
TokenKind::Ident(s) => s,
_ => return Err("Expected identifier.".into()),
};
devour_whitespace(toks);
let args = match toks.next() {
Some(Token {
kind: TokenKind::Symbol(Symbol::OpenParen),
..
}) => eat_func_args(toks, &scope, super_selector)?,
_ => return Err("expected \"(\".".into()),
};
let mut nesting = 1;
let mut body: Vec<AtRule> = Vec::new();
while nesting > 0 {
if let Some(tok) = toks.next() {
match &tok.kind {
TokenKind::AtRule(rule) => body.push(AtRule::from_tokens(
rule,
tok.pos,
toks,
&mut scope,
&Selector::new(),
)?),
TokenKind::Symbol(Symbol::CloseCurlyBrace) => nesting -= 1,
_ => {}
}
} else {
return Err("unexpected EOF (TODO: better error message)".into());
}
}
Ok((name, Function::new(scope.clone(), args, body)))
}
pub fn args(mut self, args: &mut CallArgs) -> SassResult<Function> {
for (idx, arg) in self.args.0.iter().enumerate() {
let val = match args.remove(&format!("{}", idx)) {
Some(v) => v,
None => match args.remove(&arg.name) {
Some(v) => v,
None => match &arg.default {
Some(v) => v.clone(),
None => return Err(format!("Missing argument ${}.", &arg.name).into()),
},
},
};
self.scope.insert_var(&arg.name, val)?;
}
Ok(self)
}
pub fn call(&self, super_selector: &Selector) -> SassResult<Value> {
for rule in &self.body {
match rule {
AtRule::Return(toks) => {
return Value::from_tokens(
&mut toks.clone().into_iter().peekable(),
&self.scope,
super_selector,
)
}
AtRule::For(..) => todo!("@for in function"),
_ => return Err("This at-rule is not allowed here.".into()),
}
}
todo!()
}
}