term* normalize_fuel_datatype(context *Sigma, typing_context* Delta, term* t, int fuel) { term* ans = make_datatype_term(variable_dup(t->var), t->num_args); int i; for (i = 0; i < t->num_args; i++) { ans->args[i] = normalize_fuel(Sigma, Delta, t->args[i], fuel-1); } return ans; }
/* invariant: no sharing between returned term and *any* arguments. the caller must free the result. */ term* substitute(variable* from, term* to, term* haystack) { if (haystack == NULL) return NULL; check(from != NULL && to != NULL, "substitute requires non-NULL arguments"); check(term_locally_well_formed(to), "substitute requires %W to be locally well-formed", to, print_term); check(term_locally_well_formed(haystack),"substitute requires %W to be locally well-formed", haystack, print_term); switch(haystack->tag) { case VAR: if (variable_equal(from, haystack->var)) { return term_dup(to); } else { return term_dup(haystack); } case HOLE: return term_dup(haystack); case LAM: if (variable_equal(from, haystack->var)) { return make_lambda(variable_dup(haystack->var), substitute(from, to, haystack->left), term_dup(haystack->right)); } else { if (is_free(haystack->var, to)) { variable *g = gensym(haystack->var->name); term *tg = make_var(g); term* new_haystack = make_lambda(variable_dup(g), term_dup(haystack->left), substitute(haystack->var, tg, haystack->right)); free_term(tg); term* ans = substitute(from, to, new_haystack); free_term(new_haystack); return ans; } return make_lambda(variable_dup(haystack->var), substitute(from, to, haystack->left), substitute(from, to, haystack->right)); } case PI: if (variable_equal(from, haystack->var)) { return make_pi(variable_dup(haystack->var), substitute(from, to, haystack->left), term_dup(haystack->right)); } else { if (is_free(haystack->var, to)) { variable *g = gensym(haystack->var->name); term *tg = make_var(g); term* new_haystack = make_pi(variable_dup(g), term_dup(haystack->left), substitute(haystack->var, tg, haystack->right)); free_term(tg); term* ans = substitute(from, to, new_haystack); free_term(new_haystack); return ans; } return make_pi(variable_dup(haystack->var), substitute(from, to, haystack->left), substitute(from, to, haystack->right)); } case APP: return make_app(substitute(from, to, haystack->left), substitute(from, to, haystack->right)); case TYPE: return term_dup(haystack); case DATATYPE: { term* ans = make_datatype_term(variable_dup(haystack->var), haystack->num_params, haystack->num_indices); #define SUB_VEC(dst, src, n) do { \ int __i; \ for (__i = 0; __i < n; __i++) { \ dst[__i] = substitute(from, to, src[__i]); \ } \ } while(0) SUB_VEC(ans->params, haystack->params, haystack->num_params); SUB_VEC(ans->indices, haystack->indices, haystack->num_indices); return ans; } case INTRO: { term* ans = make_intro(variable_dup(haystack->var), substitute(from, to, haystack->left), haystack->num_args, haystack->num_params, haystack->num_indices); SUB_VEC(ans->args, haystack->args, haystack->num_args); SUB_VEC(ans->params, haystack->params, haystack->num_params); SUB_VEC(ans->indices, haystack->indices, haystack->num_indices); return ans; } case ELIM: { term* ans = make_elim(variable_dup(haystack->var), haystack->num_args, haystack->num_params, haystack->num_indices); SUB_VEC(ans->args, haystack->args, haystack->num_args); SUB_VEC(ans->params, haystack->params, haystack->num_params); SUB_VEC(ans->indices, haystack->indices, haystack->num_indices); return ans; } case IMPLICIT: return term_dup(haystack); default: sentinel("malformed term with tag %d", haystack->tag); } error: return NULL; }