diff options
| -rw-r--r-- | forth.c | 70 |
1 files changed, 67 insertions, 3 deletions
@@ -60,6 +60,45 @@ void push(stack *s, stackitem si) { } } +void not(stack *s) { + int x = pop(s); + push(s, !x); +} + +void drop(stack *s) { + pop(s); +} + +void over(stack *s) { + int x = pop(s); + int y = pop(s); + push(s, y); + push(s, x); + push(s, y); +} + +void rot(stack *s) { + int x = pop(s); + int y = pop(s); + int z = pop(s); + push(s, y); + push(s, x); + push(s, z); +} + +void swap(stack *s) { + int x = pop(s); + int y = pop(s); + push(s, x); + push(s, y); +} + +void eq(stack *s) { + int x = pop(s); + int y = pop(s); + push(s, x == y); +} + void add(stack *s) { int x = pop(s); @@ -100,8 +139,14 @@ wordop optable[OPTABLE_MAX_SIZE] = { {"-", false, sub}, {"dup", false, s_dup}, {"dump", false, dump}, + {"not", false, not}, + {"=", false, eq}, + {"swap", false, swap}, + {"drop", false, drop}, + {"over", false, over}, + {"rot", false, rot}, }; -int optablelen = 4; +int optablelen = 10; const int DEFINED_FUNC_MAX_LENGTH = 1024; const int WORD_LEN_LIMIT = 255; @@ -138,7 +183,7 @@ int defineop(int starti, char *input) { exit(1); } // add op to end of table, and increment size - optable[optablelen].word = opcode; //{opcode, true, funcscript}; + optable[optablelen].word = opcode; optable[optablelen].isscript = true; optable[optablelen].script = funcscript; optable[optablelen].scriptlen = funcscripti; @@ -211,7 +256,26 @@ void eval(stack* s, int len, char* line) { } else { // end of word if (wordi > 0) { // don't exec an empty string word[wordi] = '\0'; - exec(s, word); + if (!strcmp(word, "if")) { + stackitem predicate = pop(s); + if (!predicate) { + while (len > i && + !( + line[i-3] == 't' && + line[i-2] == 'h' && + line[i-1] == 'e' && + line[i] == 'n' + )) { + i++; + } + // if (len < i + 3) { + // // error no 'then' before EOL + // exit(1); + // } + } + } else { + exec(s, word); + } } // start new word wordi = 0; |