summaryrefslogtreecommitdiff
path: root/src/chomp/ast/substitute.rs
diff options
context:
space:
mode:
Diffstat (limited to 'src/chomp/ast/substitute.rs')
-rw-r--r--src/chomp/ast/substitute.rs447
1 files changed, 210 insertions, 237 deletions
diff --git a/src/chomp/ast/substitute.rs b/src/chomp/ast/substitute.rs
index 2008a15..80df588 100644
--- a/src/chomp/ast/substitute.rs
+++ b/src/chomp/ast/substitute.rs
@@ -1,21 +1,18 @@
-use proc_macro2::Span;
-
+use super::{
+ error::TranslateError, Alt, Call, Cat, Epsilon, Fix, Lambda, Literal, NamedExpression, Variable,
+};
use crate::chomp::{
visit::{Folder, Mapper, Visitable},
Name,
};
+use proc_macro2::Span;
-use super::{
- error::SubstituteError, Alt, Call, Cat, Epsilon, Fix, Function, Literal, NamedExpression,
- Parameter, Variable,
-};
-
-#[derive(Clone, Copy, Debug, Default)]
-pub struct DeepenVars {
+struct Deepen {
pub depth: usize,
+ pub by: usize,
}
-impl Mapper for DeepenVars {
+impl Mapper for Deepen {
type Out = ();
fn map_epsilon(
@@ -41,10 +38,8 @@ impl Mapper for DeepenVars {
cat: &mut Cat,
) -> Self::Out {
cat.first.map(self);
- cat.second.map(self);
-
- for (_, term) in &mut cat.rest {
- term.map(self);
+ for (_, other) in &mut cat.rest {
+ other.map(self);
}
}
@@ -55,10 +50,8 @@ impl Mapper for DeepenVars {
alt: &mut Alt,
) -> Self::Out {
alt.first.map(self);
- alt.second.map(self);
-
- for (_, term) in &mut alt.rest {
- term.map(self);
+ for (_, other) in &mut alt.rest {
+ other.map(self);
}
}
@@ -68,9 +61,7 @@ impl Mapper for DeepenVars {
_span: Option<Span>,
fix: &mut Fix,
) -> Self::Out {
- self.depth += 1;
fix.inner.map(self);
- self.depth -= 1;
}
fn map_variable(
@@ -80,194 +71,93 @@ impl Mapper for DeepenVars {
var: &mut Variable,
) -> Self::Out {
if var.index >= self.depth {
- var.index += 1;
+ var.index += self.by;
}
}
- fn map_parameter(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- _param: &mut Parameter,
- ) -> Self::Out {
- }
-
fn map_call(
&mut self,
_name: &mut Option<Name>,
_span: Option<Span>,
call: &mut Call,
) -> Self::Out {
+ call.on.map(self);
for arg in &mut call.args {
- arg.map(self)
+ arg.map(self);
}
}
-}
-
-#[derive(Clone, Copy, Debug, Default)]
-pub struct ShallowVars {
- pub depth: usize,
-}
-
-impl Mapper for ShallowVars {
- type Out = ();
-
- fn map_epsilon(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- _eps: &mut Epsilon,
- ) -> Self::Out {
- }
-
- fn map_literal(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- _lit: &mut Literal,
- ) -> Self::Out {
- }
- fn map_cat(
+ fn map_lambda(
&mut self,
_name: &mut Option<Name>,
_span: Option<Span>,
- cat: &mut Cat,
- ) -> Self::Out {
- cat.first.map(self);
- cat.second.map(self);
-
- for (_, term) in &mut cat.rest {
- term.map(self);
- }
- }
-
- fn map_alt(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- alt: &mut Alt,
- ) -> Self::Out {
- alt.first.map(self);
- alt.second.map(self);
-
- for (_, term) in &mut alt.rest {
- term.map(self);
- }
- }
-
- fn map_fix(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- fix: &mut Fix,
- ) -> Self::Out {
- self.depth += 1;
- fix.inner.map(self);
- self.depth -= 1;
- }
-
- fn map_variable(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- var: &mut Variable,
- ) -> Self::Out {
- if var.index >= self.depth {
- var.index -= 1;
- }
- }
-
- fn map_parameter(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- _param: &mut Parameter,
- ) -> Self::Out {
- }
-
- fn map_call(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- call: &mut Call,
+ lambda: &mut Lambda,
) -> Self::Out {
- for arg in &mut call.args {
- arg.map(self)
- }
+ self.depth += lambda.args.len();
+ lambda.inner.map(self);
+ self.depth -= lambda.args.len();
}
}
-#[derive(Clone, Debug)]
-pub struct SubstituteParams {
- pub params: Vec<NamedExpression>,
+pub struct Substitute {
+ pub index: usize,
+ pub expr: NamedExpression,
}
-impl Folder for SubstituteParams {
- type Out = Result<NamedExpression, SubstituteError>;
+impl Folder for Substitute {
+ type Out = NamedExpression;
fn fold_epsilon(&mut self, name: Option<Name>, span: Option<Span>, eps: Epsilon) -> Self::Out {
- Ok(NamedExpression {
+ NamedExpression {
name,
expr: eps.into(),
span,
- })
+ }
}
fn fold_literal(&mut self, name: Option<Name>, span: Option<Span>, lit: Literal) -> Self::Out {
- Ok(NamedExpression {
+ NamedExpression {
name,
expr: lit.into(),
span,
- })
+ }
}
fn fold_cat(&mut self, name: Option<Name>, span: Option<Span>, mut cat: Cat) -> Self::Out {
- cat.first = Box::new(cat.first.fold(self)?);
- cat.second = Box::new(cat.second.fold(self)?);
+ cat.first = Box::new(cat.first.fold(self));
cat.rest = cat
.rest
.into_iter()
- .map(|(p, term)| Ok((p, term.fold(self)?)))
- .collect::<Result<_, _>>()?;
- Ok(NamedExpression {
+ .map(|(span, e)| (span, e.fold(self)))
+ .collect();
+ NamedExpression {
name,
expr: cat.into(),
span,
- })
+ }
}
fn fold_alt(&mut self, name: Option<Name>, span: Option<Span>, mut alt: Alt) -> Self::Out {
- alt.first = Box::new(alt.first.fold(self)?);
- alt.second = Box::new(alt.second.fold(self)?);
+ alt.first = Box::new(alt.first.fold(self));
alt.rest = alt
.rest
.into_iter()
- .map(|(p, term)| Ok((p, term.fold(self)?)))
- .collect::<Result<_, _>>()?;
- Ok(NamedExpression {
+ .map(|(span, e)| (span, e.fold(self)))
+ .collect();
+ NamedExpression {
name,
expr: alt.into(),
span,
- })
+ }
}
fn fold_fix(&mut self, name: Option<Name>, span: Option<Span>, mut fix: Fix) -> Self::Out {
- for param in &mut self.params {
- param.map(&mut DeepenVars::default());
- }
-
- fix.inner = Box::new(fix.inner.fold(self)?);
-
- for param in &mut self.params {
- param.map(&mut ShallowVars::default());
- }
-
- Ok(NamedExpression {
+ fix.inner = Box::new(fix.inner.fold(self));
+ NamedExpression {
name,
expr: fix.into(),
span,
- })
+ }
}
fn fold_variable(
@@ -276,50 +166,69 @@ impl Folder for SubstituteParams {
span: Option<Span>,
var: Variable,
) -> Self::Out {
- Ok(NamedExpression {
+ if var.index == self.index {
+ self.expr.clone()
+ } else {
+ NamedExpression {
+ name,
+ expr: Variable {
+ index: if var.index > self.index {
+ var.index - 1
+ } else {
+ var.index
+ },
+ }
+ .into(),
+ span,
+ }
+ }
+ }
+
+ fn fold_call(&mut self, name: Option<Name>, span: Option<Span>, mut call: Call) -> Self::Out {
+ call.on = Box::new(call.on.fold(self));
+ call.args = call.args.into_iter().map(|e| e.fold(self)).collect();
+ NamedExpression {
name,
- expr: var.into(),
+ expr: call.into(),
span,
- })
+ }
}
- fn fold_parameter(
+ fn fold_lambda(
&mut self,
name: Option<Name>,
span: Option<Span>,
- param: Parameter,
+ mut lambda: Lambda,
) -> Self::Out {
- let mut expr = self
- .params
- .get(param.index)
- .cloned()
- .ok_or_else(|| SubstituteError::FreeParameter { param, span, name: name.clone() })?;
- expr.name = expr.name.or(name);
- expr.span = expr.span.or(span);
- Ok(expr)
- }
-
- fn fold_call(&mut self, name: Option<Name>, span: Option<Span>, mut call: Call) -> Self::Out {
- call.args = call
- .args
- .into_iter()
- .map(|arg| arg.fold(self))
- .collect::<Result<_, _>>()?;
- Ok(NamedExpression {
+ self.index += lambda.args.len();
+ lambda.inner = Box::new(lambda.inner.fold(self));
+ self.index -= lambda.args.len();
+ NamedExpression {
name,
- expr: call.into(),
+ expr: lambda.into(),
span,
- })
+ }
}
}
-#[derive(Clone, Debug)]
-pub struct InlineCalls {
- pub function: Function,
+pub struct Translate {
+ changed: bool,
}
-impl Folder for InlineCalls {
- type Out = Result<NamedExpression, SubstituteError>;
+impl Translate {
+ pub fn new() -> Self {
+ Self { changed: false }
+ }
+}
+
+impl Default for Translate {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+impl Folder for Translate {
+ type Out = Result<NamedExpression, TranslateError>;
fn fold_epsilon(&mut self, name: Option<Name>, span: Option<Span>, eps: Epsilon) -> Self::Out {
Ok(NamedExpression {
@@ -337,15 +246,7 @@ impl Folder for InlineCalls {
})
}
- fn fold_cat(&mut self, name: Option<Name>, span: Option<Span>, mut cat: Cat) -> Self::Out {
- cat.first = Box::new(cat.first.fold(self)?);
- cat.second = Box::new(cat.second.fold(self)?);
- cat.rest = cat
- .rest
- .into_iter()
- .map(|(punct, term)| Ok((punct, term.fold(self)?)))
- .collect::<Result<_, _>>()?;
-
+ fn fold_cat(&mut self, name: Option<Name>, span: Option<Span>, cat: Cat) -> Self::Out {
Ok(NamedExpression {
name,
expr: cat.into(),
@@ -353,15 +254,7 @@ impl Folder for InlineCalls {
})
}
- fn fold_alt(&mut self, name: Option<Name>, span: Option<Span>, mut alt: Alt) -> Self::Out {
- alt.first = Box::new(alt.first.fold(self)?);
- alt.second = Box::new(alt.second.fold(self)?);
- alt.rest = alt
- .rest
- .into_iter()
- .map(|(punct, term)| Ok((punct, term.fold(self)?)))
- .collect::<Result<_, _>>()?;
-
+ fn fold_alt(&mut self, name: Option<Name>, span: Option<Span>, alt: Alt) -> Self::Out {
Ok(NamedExpression {
name,
expr: alt.into(),
@@ -369,9 +262,7 @@ impl Folder for InlineCalls {
})
}
- fn fold_fix(&mut self, name: Option<Name>, span: Option<Span>, mut fix: Fix) -> Self::Out {
- fix.inner = Box::new(fix.inner.fold(self)?);
-
+ fn fold_fix(&mut self, name: Option<Name>, span: Option<Span>, fix: Fix) -> Self::Out {
Ok(NamedExpression {
name,
expr: fix.into(),
@@ -392,48 +283,130 @@ impl Folder for InlineCalls {
})
}
- fn fold_parameter(
- &mut self,
- name: Option<Name>,
- span: Option<Span>,
- param: Parameter,
- ) -> Self::Out {
+ fn fold_call(&mut self, name: Option<Name>, span: Option<Span>, call: Call) -> Self::Out {
+ let mut on = *call.on;
+ self.changed = true;
+ while self.changed {
+ self.changed = false;
+ on = on.fold(self)?;
+ }
+
+ let lambda = on
+ .expr
+ .try_into_lambda()
+ .map_err(|on| TranslateError::CallNotAFunction { on, span })?;
+
+ if lambda.args.len() != call.args.len() {
+ return Err(TranslateError::WrongArgCount {
+ lambda,
+ args: call.args,
+ span,
+ });
+ }
+
+ let mut out = *lambda.inner;
+
+ for ((i, mut arg), name) in call.args.into_iter().enumerate().zip(lambda.args).rev() {
+ arg.name = arg.name.or(Some(name));
+ arg.map(&mut Deepen { depth: 0, by: i });
+ out = out.fold(&mut Substitute {
+ index: 0,
+ expr: arg,
+ });
+ }
+
+ self.changed = true;
+ while self.changed {
+ self.changed = false;
+ out = out.fold(self)?;
+ }
+
+ self.changed = true;
+ out.name = name.or(out.name);
+ out.span = span.or(out.span);
+ Ok(out)
+ }
+
+ fn fold_lambda(&mut self, name: Option<Name>, span: Option<Span>, lambda: Lambda) -> Self::Out {
Ok(NamedExpression {
name,
- expr: param.into(),
+ expr: lambda.into(),
span,
})
}
+}
- fn fold_call(&mut self, name: Option<Name>, span: Option<Span>, mut call: Call) -> Self::Out {
- call.args = call
- .args
- .into_iter()
- .map(|arg| arg.fold(self))
- .collect::<Result<_, _>>()?;
-
- if call.name != self.function.name {
- Ok(NamedExpression {
- name,
- expr: call.into(),
- span,
- })
- } else if call.args.len() == self.function.params.len() {
- let mut expr = self
- .function
- .expr
- .clone()
- .fold(&mut SubstituteParams { params: call.args })?;
- expr.name = Some(name.or(expr.name).unwrap_or(call.name));
- expr.span = span.or(expr.span);
-
- Ok(expr)
- } else {
- Err(SubstituteError::WrongArgCount {
- call,
- expected: self.function.params.len(),
- span,
- })
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ /// Returns (/x/ x) 'index
+ fn make_expr(index: usize) -> NamedExpression {
+ let var = NamedExpression {
+ name: None,
+ expr: Variable { index: 0 }.into(),
+ span: None,
+ };
+
+ let lambda = NamedExpression {
+ name: None,
+ expr: Lambda {
+ args: vec!["x".to_owned().into()],
+ inner: Box::new(var),
+ }
+ .into(),
+ span: None,
+ };
+
+ let var = NamedExpression {
+ name: None,
+ expr: Variable { index }.into(),
+ span: None,
+ };
+
+ NamedExpression {
+ name: None,
+ expr: Call {
+ on: Box::new(lambda),
+ args: vec![var],
+ }
+ .into(),
+ span: None,
}
}
+
+ #[test]
+ fn deepen_lambda() {
+ let mut expr = make_expr(0);
+ expr.map(&mut Deepen { depth: 0, by: 1 });
+ assert_eq!(expr, make_expr(1))
+ }
+
+ #[test]
+ fn substitute_renames_bigger() {
+ let expr = make_expr(1);
+ let expr = expr.fold(&mut Substitute {
+ index: 0,
+ expr: NamedExpression {
+ name: None,
+ expr: Epsilon.into(),
+ span: None,
+ },
+ });
+ assert_eq!(expr, make_expr(0))
+ }
+
+ #[test]
+ fn translate_lambda() {
+ let expr = make_expr(1);
+ let expr = expr.fold(&mut Translate::new()).unwrap();
+ assert_eq!(
+ expr,
+ NamedExpression {
+ name: Some("x".to_owned().into()),
+ expr: Variable { index: 1 }.into(),
+ span: None
+ }
+ )
+ }
}
generated by cgit v1.2.3 (git 2.49.0) at 2025-04-30 03:17:32 +0000