Merge pull request #614 from HigherOrderCO/dont-allow-repeated-field-names

Dont allow repeated field names

CHANGELOG.md

@@ -35,6 +35,7 @@ and this project does not currently adhere to a particular versioning scheme.
 - Add `elif` chains to functional syntax. ([#596][gh-596])
 - Add local definitions to imperative syntax. ([#562][gh-562])
 - Add local definitions to functional syntax.
+- Add repeated field name error message.
 
 ## [0.2.35] - 2024-06-06
 

src/fun/parser.rs

@@ -5,7 +5,7 @@ use crate::{
     display::DisplayFn, Adt, Book, CtrField, Definition, FanKind, HvmDefinition, MatchRule, Name, Num, Op,
     Pattern, Rule, Tag, Term, STRINGS,
   },
-  imp::{parser::PyParser, Enum, Variant},
+  imp::{parser::PyParser, Enum, RepeatedNames, Variant},
   maybe_grow,
 };
 use highlight_error::highlight_error;
@@ -166,8 +166,8 @@ impl<'a> TermParser<'a> {
     // name
     if self.try_consume("(") {
       self.skip_trivia();
-      let name = self.parse_top_level_name()?;
-      let name = Name::new(format!("{typ_name}/{name}"));
+      let ctr_name = self.parse_top_level_name()?;
+      let ctr_name = Name::new(format!("{typ_name}/{ctr_name}"));
 
       fn parse_field(p: &mut TermParser) -> ParseResult<CtrField> {
         let rec = p.try_consume("~");
@@ -177,7 +177,10 @@ impl<'a> TermParser<'a> {
       }
 
       let fields = self.list_like(parse_field, "", ")", "", false, 0)?;
-      Ok((name, fields))
+      if let Some(field) = fields.find_repeated_names().into_iter().next() {
+        return Err(format!("Found a repeated field '{field}' in constructor {ctr_name}."));
+      }
+      Ok((ctr_name, fields))
     } else {
       // name
       let name = self.labelled(|p| p.parse_top_level_name(), "datatype constructor name")?;

src/imp/mod.rs

@@ -4,6 +4,7 @@ pub mod parser;
 pub mod to_fun;
 
 use crate::fun::{CtrField, Name, Num, Op};
+use indexmap::{IndexMap, IndexSet};
 use interner::global::GlobalString;
 
 #[derive(Clone, Debug)]
@@ -236,3 +237,23 @@ impl InPlaceOp {
     }
   }
 }
+
+pub trait RepeatedNames {
+  fn find_repeated_names(&self) -> IndexSet<Name>;
+}
+
+impl RepeatedNames for Vec<CtrField> {
+  fn find_repeated_names(&self) -> IndexSet<Name> {
+    let mut count = IndexMap::new();
+    for field in self.iter() {
+      *count.entry(field.nam.clone()).or_insert(0) += 1;
+    }
+    count.into_iter().filter_map(|(name, count)| if count > 1 { Some(name) } else { None }).collect()
+  }
+}
+
+impl RepeatedNames for Variant {
+  fn find_repeated_names(&self) -> IndexSet<Name> {
+    self.fields.find_repeated_names()
+  }
+}

src/imp/parser.rs

@@ -8,6 +8,8 @@ use crate::{
 };
 use TSPL::Parser;
 
+use super::RepeatedNames;
+
 pub struct PyParser<'i> {
   pub input: &'i str,
   pub index: usize,
@@ -1041,6 +1043,9 @@ impl<'a> PyParser<'a> {
     if self.starts_with("{") {
       fields = self.list_like(|p| p.parse_variant_field(), "{", "}", ",", true, 0)?;
     }
+    if let Some(field) = fields.find_repeated_names().into_iter().next() {
+      return Err(format!("Found a repeated field '{field}' in constructor {ctr_name}."));
+    }
     Ok(Variant { name: ctr_name, fields })
   }
 
@@ -1059,6 +1064,9 @@ impl<'a> PyParser<'a> {
     } else {
       vec![]
     };
+    if let Some(field) = fields.find_repeated_names().into_iter().next() {
+      return Err(format!("Found a repeated field '{field}' in object {name}."));
+    }
     if !self.is_eof() {
       self.consume_new_line()?;
     }

tests/golden_tests/parse_file/repeated_datatype_name.bend

@@ -0,0 +1,8 @@
+type Expr
+  = (Lit Int)
+  | (Plus Expr Expr)
+
+eval (Expr/Lit i) = i
+eval (Expr/Plus l r) = (+ (eval l) (eval r))
+
+main = (eval (Expr/Plus (Expr/Lit 80) (Expr/Lit 90)))

tests/snapshots/parse_file__repeated_datatype_name.bend.snap

@@ -0,0 +1,7 @@
+---
+source: tests/golden_tests.rs
+input_file: tests/golden_tests/parse_file/repeated_datatype_name.bend
+---
+Errors:
+In tests/golden_tests/parse_file/repeated_datatype_name.bend :
+Found a repeated field 'Expr' in constructor Expr/Plus.