Preprocess: basic support for #undef (#278)

laurentlb · Mar 27, 2023 · 8a69877 · 8a69877
1 parent 3bea2f3
commit 8a69877
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Showing 3 changed files with 20 additions and 0 deletions.
diff --git a/src/preprocessor.fs b/src/preprocessor.fs
@@ -39,6 +39,9 @@ type private Impl() =
 
     let parseEndLine = manyCharsTill anyChar (followedBy newline) .>> newline
 
+    // TODO: ignore the defines when status is Inactive
+    // TODO: mark defines as unknown when status is Unknown
+
     let parseDefine = parse {
         let! _ = keyword "define"
         let! name = parseIdent
@@ -47,6 +50,13 @@ type private Impl() =
         return sprintf "#define %s%s" name line
     }
 
+    let parseUndef = parse {
+        let! _ = keyword "undef"
+        let! name = parseIdent
+        defines.Remove(name) |> ignore<bool>
+        return sprintf "#undef %s" name
+    }
+
     let parseIfdef = parse {
         let! word = keyword "ifdef" <|> keyword "ifndef"
         let! ident = parseIdent
@@ -125,6 +135,8 @@ type private Impl() =
         parseIf
         parseIfdef
         parseNope
+        parseUndef
+
         parseOther
     ]
 

diff --git a/tests/unit/preprocess.frag b/tests/unit/preprocess.frag
@@ -31,4 +31,9 @@ int this_is_removed;
 void keep_else() {}
 #endif
 
+#undef DEF
+#ifdef DEF
+int removed_undefd() {}
+#endif
+
 void end() {}
diff --git a/tests/unit/preprocess.frag.expected b/tests/unit/preprocess.frag.expected
@@ -12,5 +12,8 @@ void keep_outernest()
 {}
 void keep_else()
 {}
+
+#undef DEF
+
 void end()
 {}