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Unify handling of calls #614

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merged 3 commits into from
Jan 27, 2022
Merged

Unify handling of calls #614

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3f0d292
Unify handling of calls
Kijewski Jan 4, 2022
86e8d4b
No special handling for impossible ASTs
Kijewski Jan 26, 2022
cb84e0c
Use enum instead of dyn Fn
Kijewski Jan 27, 2022
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115 changes: 36 additions & 79 deletions askama_shared/src/generator.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -603,7 +603,7 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
// If `iter` is a call then we assume it's something that returns
// an iterator. If not then the user can explicitly add the needed
// call without issues.
Expr::MethodCall(..) | Expr::PathCall(..) | Expr::Index(..) => {
Expr::Call(..) | Expr::Index(..) => {
buf.writeln(&format!("let _iter = ({}).into_iter();", expr_code))
}
// If accessing `self` then it most likely needs to be
Expand Down Expand Up @@ -1049,9 +1049,7 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
Expr::StrLit(s) => self.visit_str_lit(buf, s),
Expr::CharLit(s) => self.visit_char_lit(buf, s),
Expr::Var(s) => self.visit_var(buf, s),
Expr::VarCall(var, ref args) => self.visit_var_call(buf, var, args)?,
Expr::Path(ref path) => self.visit_path(buf, path),
Expr::PathCall(ref path, ref args) => self.visit_path_call(buf, path, args)?,
Expr::Array(ref elements) => self.visit_array(buf, elements)?,
Expr::Attr(ref obj, name) => self.visit_attr(buf, obj, name)?,
Expr::Index(ref obj, ref key) => self.visit_index(buf, obj, key)?,
Expand All @@ -1060,9 +1058,7 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
Expr::BinOp(op, ref left, ref right) => self.visit_binop(buf, op, left, right)?,
Expr::Range(op, ref left, ref right) => self.visit_range(buf, op, left, right)?,
Expr::Group(ref inner) => self.visit_group(buf, inner)?,
Expr::MethodCall(ref obj, method, ref args) => {
self.visit_method_call(buf, obj, method, args)?
}
Expr::Call(ref obj, ref args) => self.visit_call(buf, obj, args)?,
Expr::RustMacro(name, args) => self.visit_rust_macro(buf, name, args),
})
}
Expand Down Expand Up @@ -1234,20 +1230,15 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
buf.write("&(");
}

let scoped = matches!(
arg,
Expr::Filter(_, _)
| Expr::MethodCall(_, _, _)
| Expr::VarCall(_, _)
| Expr::PathCall(_, _)
);

if scoped {
buf.writeln("{")?;
self.visit_expr(buf, arg)?;
buf.writeln("}")?;
} else {
self.visit_expr(buf, arg)?;
match arg {
Expr::Call(left, _) if !matches!(left.as_ref(), Expr::Path(_)) => {
buf.writeln("{")?;
self.visit_expr(buf, arg)?;
buf.writeln("}")?;
}
_ => {
self.visit_expr(buf, arg)?;
}
}

if borrow {
Expand Down Expand Up @@ -1283,7 +1274,7 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
}
}
self.visit_expr(buf, obj)?;
buf.write(&format!(".{}", attr));
buf.write(&format!(".{}", normalize_identifier(attr)));
Ok(DisplayWrap::Unwrapped)
}

Expand All @@ -1301,15 +1292,14 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
Ok(DisplayWrap::Unwrapped)
}

fn visit_method_call(
fn visit_call(
&mut self,
buf: &mut Buffer,
obj: &Expr<'_>,
method: &str,
left: &Expr<'_>,
args: &[Expr<'_>],
) -> Result<DisplayWrap, CompileError> {
if matches!(obj, Expr::Var("loop")) {
match method {
match left {
Expr::Attr(left, method) if **left == Expr::Var("loop") => match *method {
"cycle" => match args {
[arg] => {
if matches!(arg, Expr::Array(arr) if arr.is_empty()) {
Expand All @@ -1329,16 +1319,27 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
_ => return Err("loop.cycle(…) expects exactly one argument".into()),
},
s => return Err(format!("unknown loop method: {:?}", s).into()),
},
left => {
match *left {
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This seems like something that could easily be forgotten, to be updated, when changing the parser. Could it maybe be "simplified" or handled in the parser, by having some enum CallKind, which is a third value of Expr::Call()? :)

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Please see my comment in #590: https://github.com/djc/askama/pull/590#discussion_r779486870. I think the list of special cases is exhaustive. I think not even the Expr::Unary(..) | Expr::BinOp(..) | Expr::Range(..) case is actually need, because the parser won't ever generate an Expr::Call(Expr::Unary(..), ..), only Call(Group(Unary(..)), ..).

Expr::Unary(..) | Expr::BinOp(..) | Expr::Range(..) => {
buf.write("(");
self.visit_expr(buf, left)?;
buf.write(")");
}
Expr::Var(name) => match self.locals.resolve(name) {
Some(resolved) => buf.write(&resolved),
None => buf.write(&format!("(&self.{})", normalize_identifier(name))),
},
ref left => {
self.visit_expr(buf, left)?;
}
}

buf.write("(");
self._visit_args(buf, args)?;
buf.write(")");
}
} else {
if let Expr::Var("self") = obj {
buf.write("self");
} else {
self.visit_expr(buf, obj)?;
}
buf.write(&format!(".{}(", normalize_identifier(method)));
self._visit_args(buf, args)?;
buf.write(")");
}
Ok(DisplayWrap::Unwrapped)
}
Expand Down Expand Up @@ -1421,24 +1422,6 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
DisplayWrap::Unwrapped
}

fn visit_path_call(
&mut self,
buf: &mut Buffer,
path: &[&str],
args: &[Expr<'_>],
) -> Result<DisplayWrap, CompileError> {
for (i, part) in path.iter().enumerate() {
if i > 0 {
buf.write("::");
}
buf.write(part);
}
buf.write("(");
self._visit_args(buf, args)?;
buf.write(")");
Ok(DisplayWrap::Unwrapped)
}

fn visit_var(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
if s == "self" {
buf.write(s);
Expand All @@ -1449,24 +1432,6 @@ impl<'a, S: std::hash::BuildHasher> Generator<'a, S> {
DisplayWrap::Unwrapped
}

fn visit_var_call(
&mut self,
buf: &mut Buffer,
s: &str,
args: &[Expr<'_>],
) -> Result<DisplayWrap, CompileError> {
buf.write("(");
let s = normalize_identifier(s);
if !self.locals.contains(&s) && s != "self" {
buf.write("self.");
}
buf.write(s);
buf.write(")(");
self._visit_args(buf, args)?;
buf.write(")");
Ok(DisplayWrap::Unwrapped)
}

fn visit_bool_lit(&mut self, buf: &mut Buffer, s: &str) -> DisplayWrap {
buf.write(s);
DisplayWrap::Unwrapped
Expand Down Expand Up @@ -1693,14 +1658,6 @@ where
}
}

fn contains(&self, key: &K) -> bool {
self.scopes.iter().rev().any(|set| set.contains_key(key))
|| match self.parent {
Some(set) => set.contains(key),
None => false,
}
}

/// Iterates the scopes in reverse and returns `Some(LocalMeta)`
/// from the first scope where `key` exists.
fn get(&self, key: &K) -> Option<&V> {
Expand Down
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