Add parsing rules for fix

tomaz1502 · Dec 6, 2024 · 86e6e9d · 86e6e9d
1 parent ccbd66a
commit 86e6e9d
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Showing 4 changed files with 10 additions and 0 deletions.
diff --git a/src/Lam/Context.hs b/src/Lam/Context.hs
@@ -81,6 +81,9 @@ eraseNames = go []
       go (id2 : lctx) gctx e2 >>= \e2' ->
       go (id3 : lctx) gctx e3 >>= \e3' ->
       Right (Case e1' id2 e2' id3 e3')
+    go lctx gctx (RawFix e) =
+      go lctx gctx e >>= \e' ->
+      Right (Fix e')
 
 parseUntypedExpr :: String -> Either String Expr
 parseUntypedExpr str =

diff --git a/src/Lam/Parser/Lexer.x b/src/Lam/Parser/Lexer.x
@@ -22,6 +22,7 @@ tokens :-
 <0> "."       { tok Dot             }
 <0> ","       { tok Comma           }
 <0> "lam"     { tok Lam             }
+<0> "fix"     { tok Fix             }
 <0> "EVAL"    { tok Eval            }
 <0> "EXIT"    { tok Exit            }
 <0> "TYPEDEF" { tok Typedef         }
@@ -72,6 +73,7 @@ data Token =
   | Dot
   | Comma
   | Lam
+  | Fix
   | Eval
   | Exit
   | Typedef

diff --git a/src/Lam/Parser/Parser.y b/src/Lam/Parser/Parser.y
@@ -38,6 +38,7 @@ import Lam.Parser.Lexer qualified as L
 
 %token
   "lam"     { L.Lam        }
+  "fix"     { L.Fix        }
   ":"       { L.Colon      }
   "::"      { L.TypeColon  }
   ";"       { L.Semicolon  }
@@ -155,6 +156,7 @@ UntypedRawExpr :: { RawExpr }
   | "proj1" UntypedRawExpr { RawUnOp Proj1 $2 }
   | "proj2" UntypedRawExpr { RawUnOp Proj2 $2 }
   | "<" UntypedRawExpr "," UntypedRawExpr ">" { RawBinOp MkPair $2 $4 }
+  | "fix" UntypedRawExpr { RawFix $2 }
   | UntypedParExpr { $1 }
 
 UntypedParExpr : "(" UntypedRawExpr ")" { $2 }
@@ -180,6 +182,7 @@ RawExpr :: { RawExpr }
   | "inl" RawExpr "as" RawTypeL { RawInl $2 $4 }
   | "inr" RawExpr "as" RawTypeL { RawInr $2 $4 }
   | "case" RawExpr "of" "inl" var "=>" RawExpr "|" "inr" var "=>" RawExpr { RawCase $2 $5 $7 $10 $12 }
+  | "fix" RawExpr { RawFix $2 }
   | ParExpr { $1 }
 
 ParExpr : "(" RawExpr ")" { $2 }

diff --git a/src/Lam/Utils.hs b/src/Lam/Utils.hs
@@ -92,6 +92,8 @@ prettyPrint = go []
         go ctx isUntyped (App e1 e2) =
            let f = go ctx isUntyped
            in unwords ["(", f e1, ".", f e2, ")"]
+        go ctx isUntyped (Fix e) =
+            unwords [ "( fix", go ctx isUntyped e, ")" ]
 
 untypedPrettyPrint, typedPrettyPrint :: Expr -> String
 untypedPrettyPrint = prettyPrint True