--- a/parser.cxx Sun Aug 12 04:45:27 2012 +0300
+++ b/parser.cxx Mon Aug 13 19:04:29 2012 +0300
@@ -201,6 +201,8 @@
MustNext ();
// Find the mark this goto statement points to
+ // TODO: This should define the mark instead of bombing
+ // out if the mark isn't found!
unsigned int m = w->FindMark (token);
if (m == MAX_MARKS)
ParserError ("unknown label `%s`!", token.chars());
@@ -221,7 +223,9 @@
// Condition
MustNext ("(");
- // Read the expression and write it. Store it to memory too for else statements.
+ // Read the expression and write it.
+ // TODO: This should be storing it into a variable first, so
+ // that else statements would be possible!
MustNext ();
DataBuffer* c = ParseExpression (TYPE_INT);
w->WriteBuffer (c);
@@ -334,6 +338,99 @@
}
// ============================================================
+ // Switch
+ if (!token.icompare ("switch")) {
+ /* This goes a bit tricky. switch is structured in the
+ * bytecode followingly:
+ * (expression)
+ * case a: goto casemark1
+ * case b: goto casemark2
+ * case c: goto casemark3
+ * goto mark1 // jump to end if no matches
+ * casemark1: ...
+ * casemark2: ...
+ * casemark3: ...
+ * mark1: // end mark
+ */
+
+ MUST_NOT_TOPLEVEL
+ PushBlockStack ();
+ MustNext ("(");
+ MustNext ();
+ w->WriteBuffer (ParseExpression (TYPE_INT));
+ MustNext (")");
+ MustNext ("{");
+ blockstack[g_BlockStackCursor].type = BLOCKTYPE_SWITCH;
+ blockstack[g_BlockStackCursor].mark1 = w->AddMark (""); // end mark
+ continue;
+ }
+
+ // ============================================================
+ if (!token.icompare ("case")) {
+ // case is only allowed inside switch
+ if (g_BlockStackCursor <= 0 || blockstack[g_BlockStackCursor].type != BLOCKTYPE_SWITCH)
+ ParserError ("`case` outside switch");
+
+ BlockInformation* info = &blockstack[g_BlockStackCursor];
+ info->casecursor++;
+ if (info->casecursor >= MAX_CASE)
+ ParserError ("too many `case` statements in one switch");
+
+ // Get the literal (Zandronum does not support expressions here)
+ MustNumber ();
+ int num = atoi (token.chars ());
+
+ MustNext (":");
+
+ // Init a mark for the case buffer
+ int m = w->AddMark ("");
+ info->casemarks[info->casecursor] = m;
+
+ // Write down the expression and case-go-to. This builds
+ // the case tree. The closing event will write the actual
+ // blocks and move the marks appropriately.
+ info->casebuffers[info->casecursor] = w->RecordBuffer = NULL;
+ w->Write<word> (DH_CASEGOTO);
+ w->Write<word> (num);
+ w->AddReference (m);
+
+ // Init a buffer for the case block, tell the object
+ // writer to record all written data to it.
+ info->casebuffers[info->casecursor] = w->RecordBuffer = new DataBuffer;
+ continue;
+ }
+
+ // ============================================================
+ // Break statement.
+ if (!token.icompare ("break")) {
+ if (!g_BlockStackCursor)
+ ParserError ("unexpected `break`");
+
+ BlockInformation* info = &blockstack[g_BlockStackCursor];
+
+ w->Write<word> (DH_GOTO);
+
+ // switch and if use mark1 for the closing point,
+ // for and while use mark2.
+ switch (info->type) {
+ case BLOCKTYPE_IF:
+ case BLOCKTYPE_SWITCH:
+ w->AddReference (info->mark1);
+ break;
+ case BLOCKTYPE_FOR:
+ case BLOCKTYPE_WHILE:
+ w->AddReference (info->mark2);
+ break;
+ default:
+ ParserError ("unexpected `break`");
+ break;
+ }
+
+ MustNext (";");
+ continue;
+ }
+
+ // ============================================================
if (!token.compare ("}")) {
// Closing brace
@@ -357,7 +454,7 @@
// Move the closing mark here since we're at the end of the while loop
w->MoveMark (info->mark2);
break;
- case BLOCKTYPE_DO:
+ case BLOCKTYPE_DO: {
MustNext ("while");
MustNext ("(");
MustNext ();
@@ -372,6 +469,30 @@
break;
}
+ case BLOCKTYPE_SWITCH: {
+ // Switch closes. Move down to the record buffer of
+ // the lower block.
+ BlockInformation* previnfo = &blockstack[g_BlockStackCursor - 1];
+ if (previnfo->casecursor != -1)
+ w->RecordBuffer = previnfo->casebuffers[previnfo->casecursor];
+ else
+ w->RecordBuffer = NULL;
+
+ // Go through all of the buffers we
+ // recorded down and write them.
+ for (unsigned int u = 0; u < MAX_CASE; u++) {
+ if (!info->casebuffers[u])
+ continue;
+
+ w->MoveMark (info->casemarks[u]);
+ w->WriteBuffer (info->casebuffers[u]);
+ }
+
+ // Move the closing mark here
+ w->MoveMark (info->mark1);
+ }
+ }
+
// Descend down the stack
g_BlockStackCursor--;
continue;
@@ -693,6 +814,11 @@
info->mark1 = 0;
info->mark2 = 0;
info->buffer1 = NULL;
+ info->casecursor = -1;
+ for (int i = 0; i < MAX_CASE; i++) {
+ info->casemarks[i] = MAX_MARKS;
+ info->casebuffers[i] = NULL;
+ }
}
DataBuffer* ScriptReader::ParseStatement (ObjWriter* w) {