// peek for the next token, ignore pragmas public Token Peek() { do { if (pt.next == null) { pt.next = NextToken(); } pt = pt.next; } while (pt.kind > maxT); // skip pragmas return pt; }
// get the next token (possibly a token already seen during peeking) public Token Scan() { if (tokens.next == null) { return NextToken(); } else { pt = tokens = tokens.next; return tokens; } }
// make sure that peeking starts at the current scan position public void ResetPeek() { pt = tokens; }
Token NextToken() { while (ch == ' ' || ch >= 9 && ch <= 10 || ch == 13 ) NextCh(); int recKind = noSym; int recEnd = pos; t = new Token(); t.pos = pos; t.col = col; t.line = line; t.charPos = charPos; int state; if (start.ContainsKey(ch)) { state = (int) start[ch]; } else { state = 0; } tlen = 0; AddCh(); /*old way switch (state) { case -1: { t.kind = eofSym; break; } // NextCh already done case 0: { if (recKind != noSym) { tlen = recEnd - t.pos; SetScannerBehindT(); } t.kind = recKind; break; } // NextCh already done <--scan3 } old way*/ //new way begin bool done = false; while(!done) { switch (state) { case -1: { t.kind = eofSym; done = true; break; } // NextCh already done case 0: { if (recKind != noSym) { tlen = recEnd - t.pos; SetScannerBehindT(); } t.kind = recKind; done = true; break; } // NextCh already done case 1: recEnd = pos; recKind = 1; if (ch >= '0' && ch <= '9' || ch >= 'A' && ch <= 'Z' || ch >= 'a' && ch <= 'z') { AddCh(); state = 1; break; } else {t.kind = 1; done = true; break;} case 2: if (ch >= '0' && ch <= '9') { AddCh(); state = 3; break; } else { state = 0; break; } case 3: recEnd = pos; recKind = 3; if (ch >= '0' && ch <= '9') { AddCh(); state = 3; break; } else {t.kind = 3; done = true; break;} case 4: recEnd = pos; recKind = 2; if (ch >= '0' && ch <= '9') { AddCh(); state = 4; break; } else if (ch == '.') { AddCh(); state = 2; break; } else {t.kind = 2; done = true; break;} case 5: {t.kind = 4; done = true; break;} case 6: {t.kind = 5; done = true; break;} case 7: {t.kind = 6; done = true; break;} case 8: {t.kind = 7; done = true; break;} case 9: {t.kind = 8; done = true; break;} case 10: {t.kind = 9; done = true; break;} case 11: {t.kind = 10; done = true; break;} case 12: {t.kind = 11; done = true; break;} case 13: {t.kind = 12; done = true; break;} } } //new way end t.val = string.Empty;//TODO performance!!! for(int i = 0; i < tlen; i++) { t.val += tval[i]; } //t.val = new String(tval, 0, tlen); return t; }
void Init() { pos = -1; line = 1; col = 0; charPos = -1; oldEols = 0; NextCh(); pt = tokens = new Token(); // first token is a dummy }