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authorGreg Brown <gmb60@cam.ac.uk>2021-04-27 13:07:27 +0100
committerGreg Brown <gmb60@cam.ac.uk>2021-04-27 13:07:27 +0100
commit51dcf19eb6f8d2127f3dedfc1d7d5326d7a8017b (patch)
tree9d66a63fa1d017cad1b4483399950bf216d58bf8 /src/chomp/ast/substitute.rs
parent61eb62dde6a62cf19d33d5c689b0c3a4f36d93c3 (diff)
Start rewrite using query system.queries
Diffstat (limited to 'src/chomp/ast/substitute.rs')
-rw-r--r--src/chomp/ast/substitute.rs412
1 files changed, 0 insertions, 412 deletions
diff --git a/src/chomp/ast/substitute.rs b/src/chomp/ast/substitute.rs
deleted file mode 100644
index 80df588..0000000
--- a/src/chomp/ast/substitute.rs
+++ /dev/null
@@ -1,412 +0,0 @@
-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;
-
-struct Deepen {
- pub depth: usize,
- pub by: usize,
-}
-
-impl Mapper for Deepen {
- 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(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- cat: &mut Cat,
- ) -> Self::Out {
- cat.first.map(self);
- for (_, other) in &mut cat.rest {
- other.map(self);
- }
- }
-
- fn map_alt(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- alt: &mut Alt,
- ) -> Self::Out {
- alt.first.map(self);
- for (_, other) in &mut alt.rest {
- other.map(self);
- }
- }
-
- fn map_fix(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- fix: &mut Fix,
- ) -> Self::Out {
- fix.inner.map(self);
- }
-
- fn map_variable(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- var: &mut Variable,
- ) -> Self::Out {
- if var.index >= self.depth {
- var.index += self.by;
- }
- }
-
- 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);
- }
- }
-
- fn map_lambda(
- &mut self,
- _name: &mut Option<Name>,
- _span: Option<Span>,
- lambda: &mut Lambda,
- ) -> Self::Out {
- self.depth += lambda.args.len();
- lambda.inner.map(self);
- self.depth -= lambda.args.len();
- }
-}
-
-pub struct Substitute {
- pub index: usize,
- pub expr: NamedExpression,
-}
-
-impl Folder for Substitute {
- type Out = NamedExpression;
-
- fn fold_epsilon(&mut self, name: Option<Name>, span: Option<Span>, eps: Epsilon) -> Self::Out {
- NamedExpression {
- name,
- expr: eps.into(),
- span,
- }
- }
-
- fn fold_literal(&mut self, name: Option<Name>, span: Option<Span>, lit: Literal) -> Self::Out {
- 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.rest = cat
- .rest
- .into_iter()
- .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.rest = alt
- .rest
- .into_iter()
- .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 {
- fix.inner = Box::new(fix.inner.fold(self));
- NamedExpression {
- name,
- expr: fix.into(),
- span,
- }
- }
-
- fn fold_variable(
- &mut self,
- name: Option<Name>,
- span: Option<Span>,
- var: Variable,
- ) -> Self::Out {
- 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: call.into(),
- span,
- }
- }
-
- fn fold_lambda(
- &mut self,
- name: Option<Name>,
- span: Option<Span>,
- mut lambda: Lambda,
- ) -> Self::Out {
- self.index += lambda.args.len();
- lambda.inner = Box::new(lambda.inner.fold(self));
- self.index -= lambda.args.len();
- NamedExpression {
- name,
- expr: lambda.into(),
- span,
- }
- }
-}
-
-pub struct Translate {
- changed: bool,
-}
-
-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 {
- name,
- expr: eps.into(),
- span,
- })
- }
-
- fn fold_literal(&mut self, name: Option<Name>, span: Option<Span>, lit: Literal) -> Self::Out {
- Ok(NamedExpression {
- name,
- expr: lit.into(),
- span,
- })
- }
-
- fn fold_cat(&mut self, name: Option<Name>, span: Option<Span>, cat: Cat) -> Self::Out {
- Ok(NamedExpression {
- name,
- expr: cat.into(),
- span,
- })
- }
-
- fn fold_alt(&mut self, name: Option<Name>, span: Option<Span>, alt: Alt) -> Self::Out {
- Ok(NamedExpression {
- name,
- expr: alt.into(),
- span,
- })
- }
-
- fn fold_fix(&mut self, name: Option<Name>, span: Option<Span>, fix: Fix) -> Self::Out {
- Ok(NamedExpression {
- name,
- expr: fix.into(),
- span,
- })
- }
-
- fn fold_variable(
- &mut self,
- name: Option<Name>,
- span: Option<Span>,
- var: Variable,
- ) -> Self::Out {
- Ok(NamedExpression {
- name,
- expr: var.into(),
- span,
- })
- }
-
- 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: lambda.into(),
- 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
- }
- )
- }
-}