[PATCH 0/1] MR11124: Draft: vbscript: Treat Default as a keyword only in class member declarations.

[Francis De Brabandere (＠francisdb)]

Native VBScript lexes Default as a keyword only when the next word is a
member kind or access modifier, so class member variables can be named
Default. A Default specification with a missing or non-Public modifier
reports error 1057 inside a class body and a generic syntax error at
global scope.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/11124

[PATCH 1/1] vbscript: Treat Default as a keyword only in class member declarations.

[Francis De Brabandere]

From: Francis De Brabandere <[e-mail]>

Native VBScript lexes Default as a keyword only when the next word is a
member kind or access modifier, so class member variables can be named
Default. A Default specification with a missing or non-Public modifier
reports error 1057 inside a class body and a generic syntax error at
global scope.
---
 dlls/vbscript/lex.c          | 40 +++++++++++++++++++++++
 dlls/vbscript/parser.y       | 11 +++++--
 dlls/vbscript/tests/lang.vbs | 62 ++++++++++++++++++++++++++++++++++++
 3 files changed, 110 insertions(+), 3 deletions(-)

diff --git a/dlls/vbscript/lex.c b/dlls/vbscript/lex.c
index db1b8b7b355..fc0b8bff30c 100644
--- a/dlls/vbscript/lex.c
+++ b/dlls/vbscript/lex.c
@@ -141,6 +141,41 @@ static int check_keyword(parser_ctx_t *ctx, const WCHAR *word, const WCHAR **lva
     return 0;
 }
 
+/* Check whether the next word matches the given lowercase keyword using
+   ASCII-only case-insensitive matching, without advancing the parser. */
+static BOOL next_word_is(const WCHAR *ptr, const WCHAR *end, const WCHAR *word)
+{
+    WCHAR c;
+
+    while(*word) {
+        if(ptr == end)
+            return FALSE;
+        c = *ptr;
+        if(c >= 'A' && c <= 'Z') c += 'a' - 'A';
+        if(c != *word)
+            return FALSE;
+        ptr++;
+        word++;
+    }
+
+    return ptr == end || !is_identifier_char(*ptr);
+}
+
+/* 'default' is a keyword only in class member declarations, where it is
+   followed by another modifier or by the member kind; anywhere else it is
+   an ordinary identifier. */
+static BOOL is_default_keyword(parser_ctx_t *ctx)
+{
+    const WCHAR *ptr = ctx->ptr;
+
+    while(ptr < ctx->end && (*ptr == ' ' || *ptr == '\t'))
+        ptr++;
+
+    return next_word_is(ptr, ctx->end, L"sub") || next_word_is(ptr, ctx->end, L"function")
+        || next_word_is(ptr, ctx->end, L"property") || next_word_is(ptr, ctx->end, L"public")
+        || next_word_is(ptr, ctx->end, L"private");
+}
+
 static int check_keywords(parser_ctx_t *ctx, const WCHAR **lval)
 {
     int min = 0, max = ARRAY_SIZE(keywords)-1, r, i;
@@ -502,9 +537,14 @@ static int parse_next_token(void *lval, unsigned *loc, parser_ctx_t *ctx)
         return parse_numeric_literal(ctx, lval);
 
     if((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) {
+        const WCHAR *word_start = ctx->ptr;
         int ret = 0;
         if(ctx->last_token != '.' && ctx->last_token != tDOT)
             ret = check_keywords(ctx, lval);
+        if(ret == tDEFAULT && !is_default_keyword(ctx)) {
+            ctx->ptr = word_start;
+            ret = 0;
+        }
         if(!ret)
             return parse_identifier(ctx, lval);
         if(ret != tREM)
diff --git a/dlls/vbscript/parser.y b/dlls/vbscript/parser.y
index fea607a8d63..ce69fea8416 100644
--- a/dlls/vbscript/parser.y
+++ b/dlls/vbscript/parser.y
@@ -96,12 +96,15 @@ static statement_t *link_statements(statement_t*,statement_t*);
 
 /* Resolve dangling Else / End If conflicts via precedence: the empty
  * EndIf_opt rule gets lower precedence than tELSE and tEND so that
- * shift (binding to innermost If) always wins. The remaining 8
+ * shift (binding to innermost If) always wins. 8 of the remaining
  * shift/reduce conflicts are benign colon-chain ambiguities where
- * bison's default shift gives the correct greedy behavior. */
+ * bison's default shift gives the correct greedy behavior. The 9th is
+ * "Public Default" in a class body, where shifting tDEFAULT correctly
+ * prefers the default-member modifier over the member-variable error
+ * production. */
 %nonassoc LOWER_THAN_ELSE
 %nonassoc tELSE tEND
-%expect 8
+%expect 9
 
 %union {
     const WCHAR *string;
@@ -599,6 +602,8 @@ ClassBody
     | tDIM DimDeclList StSep ClassBody            { $$ = add_dim_prop(ctx, $4, $2, 0); CHECK_ERROR; }
     | PropertyDecl                                { $$ = add_class_function(ctx, new_class_decl(ctx), $1); CHECK_ERROR; }
     | PropertyDecl StSep ClassBody                { $$ = add_class_function(ctx, $3, $1); CHECK_ERROR; }
+    | tDEFAULT error                              { ctx->error_loc = @1; ctx->hres = MAKE_VBSERROR(VBSE_DEFAULT_MUST_BE_PUBLIC); YYABORT; }
+    | Storage tDEFAULT error                      { ctx->error_loc = @2; ctx->hres = MAKE_VBSERROR(VBSE_DEFAULT_MUST_BE_PUBLIC); YYABORT; }
 
 PropertyDecl
     : Storage_opt tPROPERTY tGET Identifier ArgumentsDecl_opt StSep BodyStatements tEND tPROPERTY
diff --git a/dlls/vbscript/tests/lang.vbs b/dlls/vbscript/tests/lang.vbs
index acdd992cbcf..2ddcde602cf 100644
--- a/dlls/vbscript/tests/lang.vbs
+++ b/dlls/vbscript/tests/lang.vbs
@@ -3826,6 +3826,68 @@ funcCalled = ""
 'obj()
 'call ok(funcCalled = "init","funcCalled=" & funcCalled)
 
+class DefaultVarTest1
+ Public Default
+end class
+
+Set obj = New DefaultVarTest1
+obj.Default = 31
+call ok(obj.Default = 31, "obj.Default = " & obj.Default)
+
+class DefaultVarTest2
+ Public Default(2), DefaultOther
+end class
+
+Set obj = New DefaultVarTest2
+obj.Default(1) = 32
+obj.DefaultOther = 33
+call ok(obj.Default(1) = 32, "obj.Default(1) = " & obj.Default(1))
+call ok(obj.DefaultOther = 33, "obj.DefaultOther = " & obj.DefaultOther)
+
+class DefaultVarTest3
+ Private Default
+ Public Sub SetIt(v)
+    Default = v
+ End Sub
+ Public Function GetIt
+    GetIt = Default
+ End Function
+end class
+
+Set obj = New DefaultVarTest3
+obj.SetIt 34
+call ok(obj.GetIt = 34, "obj.GetIt = " & obj.GetIt)
+
+Dim Default
+Default = 35
+call ok(Default = 35, "global Default = " & Default)
+
+sub TestDefaultDeclErrors
+    on error resume next
+
+    err.clear : Execute "Class CDE1 : Default Sub S : End Sub : End Class"
+    call ok(err.number = 1057, "Default Sub err=" & err.number)
+
+    err.clear : Execute "Class CDE2 : Default Function F : End Function : End Class"
+    call ok(err.number = 1057, "Default Function err=" & err.number)
+
+    err.clear : Execute "Class CDE3 : Default Property Get P : P = 1 : End Property : End Class"
+    call ok(err.number = 1057, "Default Property Get err=" & err.number)
+
+    err.clear : Execute "Class CDE4 : Private Default Sub S : End Sub : End Class"
+    call ok(err.number = 1057, "Private Default Sub err=" & err.number)
+
+    err.clear : Execute "Class CDE5 : Default Public Sub S : End Sub : End Class"
+    call ok(err.number = 1057, "Default Public Sub err=" & err.number)
+
+    err.clear : Execute "Class CDE6 : Default Private Sub S : End Sub : End Class"
+    call ok(err.number = 1057, "Default Private Sub err=" & err.number)
+
+    err.clear : Execute "Default Sub S : End Sub"
+    call ok(err.number = 1002, "global Default Sub err=" & err.number)
+end sub
+call TestDefaultDeclErrors
+
 with nothing
 end with
 
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/11124