307 lines
6.9 KiB
C
307 lines
6.9 KiB
C
#include <stdio.h>
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typedef struct {
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unsigned int id, refs, ptr;
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char *a, *b, reg[8];
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} Rule;
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static int flip, quiet, cycles = 0x10000;
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static Rule rules[0x1000], *rules_ = rules, lambda;
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static char dict[0x8000], *dict_ = dict, empty;
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static char bank_a[0x4000], *src_ = bank_a;
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static char bank_b[0x4000], *dst_ = bank_b;
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#define spacer(c) (c <= ' ' || c == '(' || c == ')')
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static char *
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walk(char *s)
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{
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char c;
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int depth = 0;
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if(*s == '(') {
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while((c = *s++)) {
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if(c == '(') depth++;
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if(c == ')') --depth;
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if(!depth) return s;
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}
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}
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while((c = *s) && !spacer(c)) s++;
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return s;
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}
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static void
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write_reg(char r, char *reg)
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{
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char c, *cap = walk(reg);
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switch(r) {
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case ':': /* op: output */
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if(*reg == '(') reg++, --cap;
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while(reg < cap) {
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c = *reg++;
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if(c == '\\') {
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switch(*reg++) {
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case 't': putc(0x09, stdout); break;
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case 'n': putc(0x0a, stdout); break;
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case 's': putc(0x20, stdout); break;
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}
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} else
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putc(c, stdout);
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}
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return;
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case '~': { /* op: input */
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while(fread(&c, 1, 1, stdin) && c >= ' ')
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*dst_++ = c;
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if(feof(stdin))
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*dst_++ = 'E', *dst_++ = 'O', *dst_++ = 'F';
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return;
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}
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case '^': /* op: join */
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if(*reg == '(') reg++, --cap;
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while(reg < cap && (c = *reg++))
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if(!spacer(c)) *dst_++ = c;
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return;
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case '.': /* op: unwrap */
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if(*reg == '(') reg++, --cap;
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while(reg < cap) *dst_++ = *reg++;
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return;
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case '*': { /* op: explode */
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int i, depth = 0;
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if(*reg == '(' && reg[1] != ')') { /* tuple */
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reg++;
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while(reg < cap) {
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while((c = *reg) && !spacer(c))
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*dst_++ = c, reg++;
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*dst_++ = ' ';
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*dst_++ = '(', reg++, depth++;
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}
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} else /* token */
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while((c = *reg++) && !spacer(c))
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*dst_++ = c, *dst_++ = ' ', *dst_++ = '(', depth++;
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for(i = 0; i < depth; i++) *dst_++ = ')';
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return;
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}
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default:
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while(reg < cap) *dst_++ = *reg++;
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return;
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}
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}
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static int
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write_tail(char *s)
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{
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while((*dst_++ = *s++))
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;
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*dst_ = 0;
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if((flip = !flip))
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src_ = bank_b, dst_ = bank_a;
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else
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src_ = bank_a, dst_ = bank_b;
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return 1;
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}
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static int
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apply_rule(Rule *r, char *s)
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{
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unsigned int i, rid;
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char c, *a = r->a, *b = r->b, *origin = dst_, *reg, *regs[8];
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/* phase: clean regs */
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for(i = 0; i < r->ptr; i++)
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regs[i] = NULL;
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/* phase: match rule */
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while((c = *a++)) {
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if(c == '?') {
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char *pcap = walk(s);
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rid = *a++ - '0';
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if((reg = regs[rid])) { /* reg cmp */
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char *rcap = walk(reg), *pp = s;
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while(reg < rcap || pp < pcap)
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if(*reg++ != *pp++) return 0;
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} else /* reg set */
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regs[rid] = s;
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s = pcap;
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} else if(c != *s++)
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return 0;
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}
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c = *s;
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if(!spacer(c)) return 0;
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/* phase: write rule */
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while((c = *b++)) {
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if(c == '?') {
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rid = *b - '0';
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if(rid < 9 && (reg = regs[rid]))
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b++, write_reg(r->reg[rid], reg);
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else
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*dst_++ = c;
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} else
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*dst_++ = c;
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}
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if(dst_ == origin) {
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while(*s == ' ') s++;
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if(*s == ')' && *(dst_ - 1) == ' ') dst_--;
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}
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if(!quiet && r) printf("%02d %s\n", r->id, src_), ++r->refs;
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return write_tail(s);
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}
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static int
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find_reg(Rule *r, char reg)
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{
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int rid;
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for(rid = 0; rid < (int)r->ptr; rid++)
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if(r->reg[rid] == reg) return rid;
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return -1;
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}
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static char *
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compile_rule(Rule *r, int id, char *src)
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{
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char c, *cap;
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int wrapped, reg;
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r->id = id, r->ptr = 0, r->a = &empty, r->b = ∅
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/* phase: compile left */
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while((c = *src) && c == ' ') src++;
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if(c == ')' || (c == '<' && src[1] == '>')) return src;
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r->a = dict_, cap = walk(src), wrapped = c == '(';
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if(wrapped) src++, cap--;
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while(src < cap) {
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c = *src, *dict_++ = *src++;
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if(c == '?') {
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c = *src++, reg = find_reg(r, c);
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if(reg == -1 && c != '(')
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r->reg[r->ptr] = c, reg = r->ptr++;
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*dict_++ = '0' + reg;
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}
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}
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src += wrapped, *dict_++ = 0;
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/* phase: compile right */
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while((c = *src) && c == ' ') src++;
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if(c == ')' || (c == '<' && src[1] == '>')) return src;
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r->b = dict_, cap = walk(src), wrapped = c == '(';
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if(wrapped) src++, cap--;
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while(src < cap) {
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c = *src, *dict_++ = *src++;
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if(c == '?') {
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c = *src++, reg = find_reg(r, c);
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*dict_++ = reg != -1 ? '0' + reg : c;
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}
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}
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src += wrapped, *dict_++ = 0;
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return src;
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}
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static Rule *
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find_rule(char *s, char *cap)
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{
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Rule *r = rules;
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if(*s == '(') s++, cap--;
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while(r < rules_) {
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char *ss = s, *a = r->a;
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while(*ss++ == *a++)
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if(!*a && ss == cap) return r;
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r++;
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}
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return r;
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}
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static void
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echo_rule(Rule *r, char *s)
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{
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char c;
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putc('(', stdout);
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while((c = *s++)) {
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unsigned int rid;
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putc(c, stdout);
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if(c == '?')
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c = *s++, rid = c - '0', putc(rid < 9 ? r->reg[rid] : c, stdout);
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}
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putc(')', stdout), putc(' ', stdout);
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}
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static int
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rewrite(void)
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{
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char c, last = 0, *cap, *s = src_;
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while(*s == ' ') s++;
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while((c = *s)) {
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if(c == '(' || spacer(last)) {
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Rule *r = NULL;
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/* phase: define */
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if(c == '<' && s[1] == '>') {
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r = rules_++;
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s = compile_rule(r, rules_ - rules - 1, s + 2);
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if(!quiet && r->a)
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printf("<> "), echo_rule(r, r->a), echo_rule(r, r->b), putc('\n', stdout);
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while(*s == ' ') s++;
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return write_tail(s);
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}
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/* phase: undefine */
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if(c == '>' && s[1] == '<') {
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s += 2;
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while(*s == ' ') s++;
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cap = walk(s), r = find_rule(s, cap);
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if(!quiet && r->a)
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printf(">< "), echo_rule(r, r->a), echo_rule(r, r->b), putc('\n', stdout);
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r->a = 0;
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while(*cap == ' ') cap++;
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return write_tail(cap);
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}
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/* phase: lambda */
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if(c == '?' && s[1] == '(') {
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cap = walk(s + 1), compile_rule(&lambda, -1, s + 2), s = cap;
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while(*s == ' ') s++;
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if(!apply_rule(&lambda, s)) write_tail(s);
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return 1;
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}
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/* phase: match */
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for(r = rules; r < rules_; r++)
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if(r->a && apply_rule(r, s)) return 1;
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}
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*dst_++ = last = c;
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s++;
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}
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*dst_++ = 0;
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return 0;
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}
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int
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main(int argc, char **argv)
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{
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FILE *f;
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int i, pl = 0, pr = 0, rw = 0;
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char c, last = 0, *w = bank_a;
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if(argc < 2)
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return !printf("usage: modal [-vqn] source.modal\n");
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for(i = 1; i < argc && *argv[i] == '-'; i++) {
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switch(argv[i][1]) {
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case 'v': /* version */ return !printf("Modal Interpreter, 27 Apr 2024.\n");
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case 'q': /* quiet */ quiet = 1; break;
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case 'n': /* infinite */ cycles = 0xffffffff; break;
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}
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}
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if(!(f = fopen(argv[i], "r")))
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return !printf("Modal file invalid: %s.\n", argv[i]);
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while(fread(&c, 1, 1, f)) {
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c = c <= 0x20 ? 0x20 : c;
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if(c == ' ' && last == '(') continue;
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if(c == ')' && last == ' ') w--;
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if(c == ' ' && last == ' ') w--;
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if(c == '(') pl++;
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if(c == ')') pr++;
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if(c == '(' && last != '?' && !spacer(last)) *w++ = ' ';
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if(last == ')' && !spacer(c)) *w++ = ' ';
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*w++ = last = c;
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}
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while(*(--w) <= ' ') *w = 0;
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fclose(f);
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if(pr != pl)
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return !printf("Modal program imbalanced.\n");
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while(rewrite() && ++rw)
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if(!cycles--) return !printf("Modal rewrites exceeded.\n");
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if(!quiet) {
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while(rules_-- > rules)
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if(!rules_->refs && rules_->a)
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printf("-- Unused rule: %d <> (%s) (%s)\n", rules_->refs, rules_->a, rules_->b);
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printf(".. %s\nCompleted in %d rewrites.\n", src_, rw);
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}
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return 0;
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} |