diff options
Diffstat (limited to 'compile.c')
| -rw-r--r-- | compile.c | 78 |
1 files changed, 60 insertions, 18 deletions
@@ -2953,30 +2953,72 @@ CORD compile(env_t *env, ast_t *ast) } case If: { auto if_ = Match(ast, If); - if (!if_->else_body) - code_err(ast, "'if' expressions can only be used if you also have an 'else' block"); + ast_t *condition = if_->condition; + CORD decl_code = CORD_EMPTY; + env_t *truthy_scope = env, *falsey_scope = env; - type_t *t = get_type(env, ast); - if (t->tag == VoidType || t->tag == AbortType) - code_err(ast, "This expression has a %T type, but it needs to have a real value", t); + type_t *condition_type; + if (condition->tag == Declare) { + condition_type = get_type(env, Match(condition, Declare)->value); - CORD condition; - if (get_type(env, if_->condition)->tag == TextType) - condition = CORD_all("(", compile(env, if_->condition), ").length"); - else - condition = compile(env, if_->condition); + const char *varname = Match(Match(condition, Declare)->var, Var)->name; + falsey_scope = fresh_scope(env); + bind_statement(falsey_scope, condition); + binding_t *b = get_binding(falsey_scope, varname); + assert(b); + + truthy_scope = fresh_scope(env); + set_binding(truthy_scope, varname, + new(binding_t, .type=Match(condition_type, OptionalType)->type, .code=b->code)); + + decl_code = compile_statement(env, condition); + condition = Match(condition, Declare)->var; + } else if (condition->tag == Var) { + condition_type = get_type(env, condition); + if (condition_type->tag == OptionalType) { + truthy_scope = fresh_scope(env); + const char *varname = Match(if_->condition, Var)->name; + binding_t *b = get_binding(env, varname); + if (!b) code_err(condition, "I don't know what this variable refers to"); + set_binding(truthy_scope, varname, + new(binding_t, .type=Match(condition_type, OptionalType)->type, .code=b->code)); + } + } else { + condition_type = get_type(env, condition); + } + + if (condition_type->tag == PointerType) + code_err(condition, "This pointer will always be non-null, so it should not be used in a conditional."); + + CORD condition_code; + if (condition_type->tag == TextType) { + condition_code = CORD_all("(", compile(env, condition), ").length"); + } else if (condition_type->tag == ArrayType) { + condition_code = CORD_all("(", compile(env, condition), ").length"); + } else if (condition_type->tag == TableType || condition_type->tag == SetType) { + condition_code = CORD_all("(", compile(env, condition), ").entries.length"); + } else if (condition_type->tag == OptionalType) { + condition_code = CORD_all("!", check_null(condition_type, compile(env, condition))); + } else if (condition_type->tag == BoolType) { + condition_code = compile(env, condition); + } else { + code_err(condition, "%T values cannot be used for conditionals", condition_type); + } - type_t *true_type = get_type(env, if_->body); - type_t *false_type = get_type(env, if_->else_body); + type_t *true_type = get_type(truthy_scope, if_->body); + type_t *false_type = get_type(falsey_scope, if_->else_body); if (true_type->tag == AbortType || true_type->tag == ReturnType) - return CORD_all("({ if (", condition, ") ", compile_statement(env, if_->body), - "\n", compile(env, if_->else_body), "; })"); + return CORD_all("({ ", decl_code, "if (", condition_code, ") ", compile_statement(truthy_scope, if_->body), + "\n", compile(falsey_scope, if_->else_body), "; })"); else if (false_type->tag == AbortType || false_type->tag == ReturnType) - return CORD_all("({ if (!(", condition, ")) ", compile_statement(env, if_->else_body), - "\n", compile(env, if_->body), "; })"); + return CORD_all("({ ", decl_code, "if (!(", condition_code, ")) ", compile_statement(falsey_scope, if_->else_body), + "\n", compile(truthy_scope, if_->body), "; })"); + else if (decl_code != CORD_EMPTY) + return CORD_all("({ ", decl_code, "(", condition_code, ") ? ", compile(truthy_scope, if_->body), " : ", + compile(falsey_scope, if_->else_body), ";})"); else - return CORD_all("((", condition, ") ? ", - compile(env, if_->body), " : ", compile(env, if_->else_body), ")"); + return CORD_all("((", condition_code, ") ? ", + compile(truthy_scope, if_->body), " : ", compile(falsey_scope, if_->else_body), ")"); } case Reduction: { auto reduction = Match(ast, Reduction); |