changeset
Added support for else-statements
Sat, 25 Aug 2012 03:40:36 +0300
- author
- Teemu Piippo <crimsondusk64@gmail.com>
- date
- Sat, 25 Aug 2012 03:40:36 +0300
- changeset 56
- 384c5605bda9
- parent 55
- 173956c1ac27
- child 57
- 96f60ca748a0
Added support for else-statements
| main.cxx | file | annotate | diff | comparison | revisions | |
| parser.cxx | file | annotate | diff | comparison | revisions | |
| scriptreader.h | file | annotate | diff | comparison | revisions |
--- a/main.cxx Sat Aug 25 03:04:14 2012 +0300 +++ b/main.cxx Sat Aug 25 03:40:36 2012 +0300 @@ -61,6 +61,7 @@ "case", "default", "do", + "else", "event", "for", "goto", @@ -76,7 +77,6 @@ // These ones aren't implemented yet but I plan to do so, thus they are // reserved. Also serves as a to-do list of sorts for me. >:F "continue", - "else", "enum", // Would enum actually be useful? I think so. "func", // Would function support need external support from zandronum? "return",
--- a/parser.cxx Sat Aug 25 03:04:14 2012 +0300 +++ b/parser.cxx Sat Aug 25 03:40:36 2012 +0300 @@ -57,6 +57,8 @@ #define MUST_NOT_TOPLEVEL if (g_CurMode == MODE_TOPLEVEL) \ ParserError ("%s-statements may not be defined at top level!", token.chars()); +#define SCOPE(n) blockstack[g_BlockStackCursor - n] + int g_NumStates = 0; int g_NumEvents = 0; int g_CurMode = MODE_TOPLEVEL; @@ -71,6 +73,10 @@ // and writes the data to the object file via ObjWriter - which also takes care // of necessary buffering so stuff is written in the correct order. void ScriptReader::ParseBotScript (ObjWriter* w) { + // Zero the entire block stack first + for (int i = 0; i < MAX_STRUCTSTACK; i++) + memset (&blockstack[i], 0, sizeof (BlockInformation)); + while (Next()) { // ============================================================ if (!token.compare ("state")) { @@ -207,8 +213,6 @@ MustNext ("("); // 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); @@ -226,8 +230,34 @@ w->AddReference (marknum); // Store it in the block stack - blockstack[g_BlockStackCursor].mark1 = marknum; - blockstack[g_BlockStackCursor].type = BLOCKTYPE_IF; + SCOPE(0).mark1 = marknum; + SCOPE(0).type = BLOCKTYPE_IF; + continue; + } + + if (!token.compare ("else")) { + MUST_NOT_TOPLEVEL + MustNext ("{"); + + // Don't use PushBlockStack as that will reset the scope. + g_BlockStackCursor++; + if (g_BlockStackCursor >= MAX_STRUCTSTACK) + ParserError ("too deep scope"); + + if (SCOPE(0).type != BLOCKTYPE_IF) + ParserError ("else without preceding if"); + + // Write down to jump to the end of the else statement + // Otherwise we have fall-throughs + SCOPE(0).mark2 = w->AddMark (""); + + // Instruction to jump to the end after if block is complete + w->Write (DH_GOTO); + w->AddReference (SCOPE(0).mark2); + + // Move the ifnot mark here and set type to else + w->MoveMark (SCOPE(0).mark1); + SCOPE(0).type = BLOCKTYPE_ELSE; continue; } @@ -259,9 +289,9 @@ w->AddReference (mark2); // Store the needed stuff - blockstack[g_BlockStackCursor].mark1 = mark1; - blockstack[g_BlockStackCursor].mark2 = mark2; - blockstack[g_BlockStackCursor].type = BLOCKTYPE_WHILE; + SCOPE(0).mark1 = mark1; + SCOPE(0).mark2 = mark2; + SCOPE(0).type = BLOCKTYPE_WHILE; continue; } @@ -301,10 +331,10 @@ w->AddReference (mark2); // Store the marks and incrementor - blockstack[g_BlockStackCursor].mark1 = mark1; - blockstack[g_BlockStackCursor].mark2 = mark2; - blockstack[g_BlockStackCursor].buffer1 = incr; - blockstack[g_BlockStackCursor].type = BLOCKTYPE_FOR; + SCOPE(0).mark1 = mark1; + SCOPE(0).mark2 = mark2; + SCOPE(0).buffer1 = incr; + SCOPE(0).type = BLOCKTYPE_FOR; continue; } @@ -314,8 +344,8 @@ MUST_NOT_TOPLEVEL PushBlockStack (); MustNext ("{"); - blockstack[g_BlockStackCursor].mark1 = w->AddMark (""); - blockstack[g_BlockStackCursor].type = BLOCKTYPE_DO; + SCOPE(0).mark1 = w->AddMark (""); + SCOPE(0).type = BLOCKTYPE_DO; continue; } @@ -342,17 +372,16 @@ w->WriteBuffer (ParseExpression (TYPE_INT)); MustNext (")"); MustNext ("{"); - blockstack[g_BlockStackCursor].type = BLOCKTYPE_SWITCH; - blockstack[g_BlockStackCursor].mark1 = w->AddMark (""); // end mark - blockstack[g_BlockStackCursor].buffer1 = NULL; // default header + SCOPE(0).type = BLOCKTYPE_SWITCH; + SCOPE(0).mark1 = w->AddMark (""); // end mark + SCOPE(0).buffer1 = NULL; // default header continue; } // ============================================================ if (!token.compare ("case")) { // case is only allowed inside switch - BlockInformation* info = &blockstack[g_BlockStackCursor]; - if (info->type != BLOCKTYPE_SWITCH) + if (SCOPE(0).type != BLOCKTYPE_SWITCH) ParserError ("case label outside switch"); // Get the literal (Zandronum does not support expressions here) @@ -361,7 +390,7 @@ MustNext (":"); for (int i = 0; i < MAX_CASE; i++) - if (info->casenumbers[i] == num) + if (SCOPE(0).casenumbers[i] == num) ParserError ("multiple case %d labels in one switch", num); // Write down the expression and case-go-to. This builds @@ -376,16 +405,15 @@ w->Write<word> (DH_CASEGOTO); w->Write<word> (num); AddSwitchCase (w, NULL); - info->casenumbers[info->casecursor] = num; + SCOPE(0).casenumbers[SCOPE(0).casecursor] = num; continue; } if (!token.compare ("default")) { - BlockInformation* info = &blockstack[g_BlockStackCursor]; - if (info->type != BLOCKTYPE_SWITCH) + if (SCOPE(0).type != BLOCKTYPE_SWITCH) ParserError ("default label outside switch"); - if (info->buffer1) + if (SCOPE(0).buffer1) ParserError ("multiple default labels in one switch"); MustNext (":"); @@ -398,7 +426,7 @@ // to pop it with DH_DROP manually if we end up in // a default. DataBuffer* b = new DataBuffer; - info->buffer1 = b; + SCOPE(0).buffer1 = b; b->Write<word> (DH_DROP); b->Write<word> (DH_GOTO); AddSwitchCase (w, b); @@ -411,20 +439,18 @@ 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) { + switch (SCOPE(0).type) { case BLOCKTYPE_IF: case BLOCKTYPE_SWITCH: - w->AddReference (info->mark1); + w->AddReference (SCOPE(0).mark1); break; case BLOCKTYPE_FOR: case BLOCKTYPE_WHILE: - w->AddReference (info->mark2); + w->AddReference (SCOPE(0).mark2); break; default: ParserError ("unexpected `break`"); @@ -458,23 +484,27 @@ // If we're in the block stack, we're descending down from it now if (g_BlockStackCursor > 0) { - BlockInformation* info = &blockstack[g_BlockStackCursor]; - switch (info->type) { + switch (SCOPE(0).type) { case BLOCKTYPE_IF: // Adjust the closing mark. - w->MoveMark (info->mark1); + w->MoveMark (SCOPE(0).mark1); + break; + case BLOCKTYPE_ELSE: + // else instead uses mark1 for itself (so if expression + // fails, jump to else), mark2 means end of else + w->MoveMark (SCOPE(0).mark2); break; case BLOCKTYPE_FOR: // Write the incrementor at the end of the loop block - w->WriteBuffer (info->buffer1); + w->WriteBuffer (SCOPE(0).buffer1); // fall-thru case BLOCKTYPE_WHILE: // Write down the instruction to go back to the start of the loop w->Write (DH_GOTO); - w->AddReference (info->mark1); + w->AddReference (SCOPE(0).mark1); // Move the closing mark here since we're at the end of the while loop - w->MoveMark (info->mark2); + w->MoveMark (SCOPE(0).mark2); break; case BLOCKTYPE_DO: { MustNext ("while"); @@ -487,41 +517,40 @@ // If the condition runs true, go back to the start. w->WriteBuffer (expr); w->Write<long> (DH_IFGOTO); - w->AddReference (info->mark1); + w->AddReference (SCOPE(0).mark1); 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->SwitchBuffer = previnfo->casebuffers[previnfo->casecursor]; + if (SCOPE(1).casecursor != -1) + w->SwitchBuffer = SCOPE(1).casebuffers[SCOPE(1).casecursor]; else w->SwitchBuffer = NULL; // If there was a default in the switch, write its header down now. // If not, write instruction to jump to the end of switch after // the headers (thus won't fall-through if no case matched) - if (info->buffer1) - w->WriteBuffer (info->buffer1); + if (SCOPE(0).buffer1) + w->WriteBuffer (SCOPE(0).buffer1); else { w->Write<word> (DH_DROP); w->Write<word> (DH_GOTO); - w->AddReference (info->mark1); + w->AddReference (SCOPE(0).mark1); } // 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]) + if (!SCOPE(0).casebuffers[u]) continue; - w->MoveMark (info->casemarks[u]); - w->WriteBuffer (info->casebuffers[u]); + w->MoveMark (SCOPE(0).casemarks[u]); + w->WriteBuffer (SCOPE(0).casebuffers[u]); } // Move the closing mark here - w->MoveMark (info->mark1); + w->MoveMark (SCOPE(0).mark1); } } @@ -713,8 +742,8 @@ MustNext (); DataBuffer* rb = ParseExprValue (reqtype); - // Ternary operator requires - naturally - a third operator if (oper == OPER_TERNARY) { + // Ternary operator requires - naturally - a third operand. MustNext (":"); MustNext (); DataBuffer* tb = ParseExprValue (reqtype); @@ -952,7 +981,10 @@ void ScriptReader::PushBlockStack () { g_BlockStackCursor++; - BlockInformation* info = &blockstack[g_BlockStackCursor]; + if (g_BlockStackCursor >= MAX_STRUCTSTACK) + ParserError ("too deep scope"); + + BlockInformation* info = &SCOPE(0); info->type = 0; info->mark1 = 0; info->mark2 = 0; @@ -978,7 +1010,7 @@ } void ScriptReader::AddSwitchCase (ObjWriter* w, DataBuffer* b) { - BlockInformation* info = &blockstack[g_BlockStackCursor]; + BlockInformation* info = &SCOPE(0); info->casecursor++; if (info->casecursor >= MAX_CASE)
--- a/scriptreader.h Sat Aug 25 03:04:14 2012 +0300 +++ b/scriptreader.h Sat Aug 25 03:40:36 2012 +0300 @@ -194,11 +194,13 @@ // Block types enum { + BLOCKTYPE_UNSET = 0, BLOCKTYPE_IF, BLOCKTYPE_WHILE, BLOCKTYPE_FOR, BLOCKTYPE_DO, BLOCKTYPE_SWITCH, + BLOCKTYPE_ELSE, }; #endif // __SCRIPTREADER_H__ \ No newline at end of file
