data_t *eval(const data_t *exp, data_t *env) { if(eval_plz_die) { eval_plz_die = 0; ExitThread(0); } if(is_self_evaluating(exp)) return (data_t*)exp; if(is_variable(exp)) return lookup_variable_value(exp, env); if(is_quoted_expression(exp)) return get_text_of_quotation(exp); if(is_assignment(exp)) return eval_assignment(exp, env); if(is_definition(exp)) return eval_definition(exp, env); if(is_if(exp)) return eval_if(exp, env); if(is_lambda(exp)) return make_procedure(get_lambda_parameters(exp), get_lambda_body(exp), env); if(is_begin(exp)) return eval_sequence(get_begin_actions(exp), env); if(is_cond(exp)) return eval(cond_to_if(exp), env); if(is_letrec(exp)) return eval(letrec_to_let(exp), env); if(is_let_star(exp)) return eval(let_star_to_nested_lets(exp), env); if(is_let(exp)) return eval(let_to_combination(exp), env); if(is_application(exp)) return apply( eval(get_operator(exp), env), get_list_of_values(get_operands(exp), env)); printf("Unknown expression type -- EVAL '"); return make_symbol("error"); }
object *eval(object *exp, object *env) { object *procedure; object *arguments; object *result; bool tailcall = false; do { if (is_self_evaluating(exp)) return exp; if (is_variable(exp)) return lookup_variable_value(exp, env); if (is_quoted(exp)) return text_of_quotation(exp); if (is_assignment(exp)) return eval_assignment(exp, env); if (is_definition(exp)) return eval_definition(exp, env); if (is_if(exp)) { exp = is_true(eval(if_predicate(exp), env)) ? if_consequent(exp) : if_alternative(exp); tailcall = true; continue; } if (is_lambda(exp)) return make_compound_proc(lambda_parameters(exp), lambda_body(exp), env); if (is_begin(exp)) { exp = begin_actions(exp); while (!is_last_exp(exp)) { eval(first_exp(exp), env); exp = rest_exps(exp); } exp = first_exp(exp); tailcall = true; continue; } if (is_cond(exp)) { exp = cond_to_if(exp); tailcall = true; continue; } if (is_let(exp)) { exp = let_to_application(exp); tailcall = true; continue; } if (is_and(exp)) { exp = and_tests(exp); if (is_empty(exp)) return make_boolean(true); while (!is_last_exp(exp)) { result = eval(first_exp(exp), env); if (is_false(result)) return result; exp = rest_exps(exp); } exp = first_exp(exp); tailcall = true; continue; } if (is_or(exp)) { exp = or_tests(exp); if (is_empty(exp)) { return make_boolean(false); } while (!is_last_exp(exp)) { result = eval(first_exp(exp), env); if (is_true(result)) return result; exp = rest_exps(exp); } exp = first_exp(exp); tailcall = true; continue; } if (is_application(exp)) { procedure = eval(operator(exp), env); arguments = list_of_values(operands(exp), env); if (is_primitive_proc(procedure) && procedure->data.primitive_proc.fn == eval_proc) { exp = eval_expression(arguments); env = eval_environment(arguments); tailcall = true; continue; } if (is_primitive_proc(procedure) && procedure->data.primitive_proc.fn == apply_proc) { procedure = apply_operator(arguments); arguments = apply_operands(arguments); } if (is_primitive_proc(procedure)) return (procedure->data.primitive_proc.fn)(arguments); if (is_compound_proc(procedure)) { env = extend_environment(procedure->data.compound_proc.parameters, arguments, procedure->data.compound_proc.env); exp = make_begin(procedure->data.compound_proc.body); tailcall = true; continue; } return make_error(342, "unknown procedure type"); } // is_application() } while (tailcall); fprintf(stderr, "cannot eval unknown expression type\n"); exit(EXIT_FAILURE); }
object *bs_eval(object *exp, object *env) { tailcall: if (is_empty_list(exp)) { error("unable to evaluate empty list"); } else if (is_self_evaluating(exp)) { return exp; } else if (is_variable(exp)) { return lookup_variable_value(exp, env); } else if (is_quoted(exp)) { return quoted_expression(exp); } else if (is_assignment(exp)) { return eval_assignment(exp, env); } else if (is_definition(exp)) { return eval_definition(exp, env); } else if (is_if(exp)) { if (is_true(bs_eval(if_predicate(exp), env))) { exp = if_consequent(exp); } else { exp = if_alternate(exp); } goto tailcall; } else if (is_lambda(exp)) { return make_compound_proc(lambda_parameters(exp), lambda_body(exp), env); } else if (is_begin(exp)) { exp = begin_actions(exp); if (is_empty_list(exp)) { error("empty begin block"); } while (!is_empty_list(cdr(exp))) { bs_eval(car(exp), env); exp = cdr(exp); } exp = car(exp); goto tailcall; } else if (is_cond(exp)) { exp = cond_to_if(exp); goto tailcall; } else if (is_let(exp)) { exp = let_to_application(exp); goto tailcall; } else if (is_and(exp)) { exp = and_tests(exp); if (is_empty_list(exp)) { return get_boolean(1); } object *result; while (!is_empty_list(cdr(exp))) { result = bs_eval(car(exp), env); if (is_false(result)) { return result; } exp = cdr(exp); } exp = car(exp); goto tailcall; } else if (is_or(exp)) { exp = or_tests(exp); if (is_empty_list(exp)) { return get_boolean(0); } object *result; while (!is_empty_list(cdr(exp))) { result = bs_eval(car(exp), env); if (is_true(result)) { return result; } exp = cdr(exp); } exp = car(exp); goto tailcall; } else if (is_application(exp)) { object *procedure = bs_eval(application_operator(exp), env); object *parameters = eval_parameters(application_operands(exp), env); // handle eval specially for tailcall requirement. if (is_primitive_proc(procedure) && procedure->value.primitive_proc == eval_proc) { exp = eval_expression(parameters); env = eval_environment(parameters); goto tailcall; } // handle apply specially for tailcall requirement. if (is_primitive_proc(procedure) && procedure->value.primitive_proc == apply_proc) { procedure = apply_operator(parameters); parameters = apply_operands(parameters); } if (is_primitive_proc(procedure)) { return (procedure->value.primitive_proc)(parameters); } else if (is_compound_proc(procedure)) { env = extend_environment( procedure->value.compound_proc.parameters, parameters, procedure->value.compound_proc.env); exp = make_begin(procedure->value.compound_proc.body); goto tailcall; } else { error("unable to apply unknown procedure type"); } } else { error("unable to evaluate expression"); } }
static pSlipObject slip_eval(pSlip gd, pSlipObject exp, pSlipEnvironment env) { pSlipObject proc; pSlipObject args; tailcall: if (is_self_evaluating(exp) == S_TRUE) { return exp; } else if (is_variable(exp) == S_TRUE) { return lookup_variable_value(gd, exp, env); } else if (is_quoted(gd, exp) == S_TRUE) { return text_of_quotation(exp); } else if (is_assignment(gd, exp) == S_TRUE) { return eval_assignment(gd, exp, env); } else if (is_definition(gd, exp) == S_TRUE) { return eval_definition(gd, exp, env); } else if (is_if(gd, exp) == S_TRUE) { exp = is_true(gd, slip_eval(gd, if_predicate(exp), env)) == S_TRUE ? if_consequent(exp) : if_alternative(gd, exp); goto tailcall; } else if (is_lambda(gd, exp) == S_TRUE) { return s_NewCompoundProc(gd, lambda_parameters(exp), lambda_body(exp), env); } else if (is_begin(gd, exp) == S_TRUE) { exp = begin_actions(exp); while (!is_last_exp(gd, exp)) { slip_eval(gd, first_exp(exp), env); exp = rest_exps(exp); } exp = first_exp(exp); goto tailcall; } else if (is_cond(gd, exp) == S_TRUE) { exp = cond_to_if(gd, exp); goto tailcall; } else if (is_let(gd, exp) == S_TRUE) { exp = let_to_application(gd, exp); goto tailcall; } else if (is_application(exp) == S_TRUE) { proc = slip_eval(gd, slip_operator(exp), env); if (proc == NULL) return gd->singleton_False; if (proc->type == eType_PRIMITIVE_PROC || proc->type == eType_COMPOUND_PROC) { args = list_of_values(gd, operands(exp), env); if (args == NULL) return gd->singleton_False; if (sIsObject_PrimitiveProc(proc) == S_TRUE) { return proc->data.prim_proc.func(gd, args); } else if (sIsObject_CompoundProc(proc) == S_TRUE) { env = setup_environment(gd, proc->data.comp_proc.env, proc->data.comp_proc.params, args); exp = make_begin(gd, proc->data.comp_proc.code); goto tailcall; } else { throw_error(gd, "unknown procedure type\n"); return gd->singleton_False; } } else return proc; } else { throw_error(gd, "cannot eval unknown expression type\n"); return NULL; } throw_error(gd, "what??\n"); return NULL; }
static Token next_token (void) { Token token; restart: outbuffer_off(); outbuffer_on(); token.startindex = out.buffindex; { int c = next_char(); switch (c) { case EOF: /* EOF */ token.type = eof; goto done; case ' ': case '\v': case '\t': case '\n': /* whitespace, ignore */ goto restart; case '\\': if (peek_char()=='\n') { /* backslash newline, ignore */ next_char(); goto restart; } goto separator; case '/': if (peek_char() == '*') { /* Comment */ next_char(); while (1) { c = next_char(); if (c==EOF) { fprintf(stderr,"Unfinished comment\n"); break; } if ((c=='*') && (peek_char()=='/')) { next_char(); break; } } goto restart; } goto separator; case '*': if (peek_char() == '/') fprintf(stderr,"End of comment outside comment in line %lu\n",input_line); goto separator; case '#': /* preprocessor directive */ { char* line = next_line(); if (line) { char* old_line = line; line = concat2("#",line); xfree(old_line); } else line = concat1("#"); while (line[strlen(line)-1] == '\\') { char* continuation_line = next_line(); line[strlen(line)-1] = '\0'; if (continuation_line) { char* old_line = line; line = concat2(line,continuation_line); xfree(old_line); xfree(continuation_line); } } { const char* condition; long line_directive; if ((condition = is_if(line)) != NULL) { do_if(condition); } else if (is_else(line)) { do_else(); line_repeat_else(); } else if ((condition = is_elif(line)) != NULL) { do_elif(condition); line_repeat_else(); } else if (is_endif(line)) { do_endif(); line_repeat_endif(); } else if ((line_directive = decode_line_directive(line)) >= 0) input_line = line_directive; #ifdef SPLIT_OBJECT_INITIALIZATIONS else { /* Replace "var object foo = ..." with "var object foo; foo = ..." in macros as well. */ if (out.buffindex < MAXHEADERLEN) { uintB* p; out.buffer[out.buffindex] = '\0'; for (p = &out.buffer[token.startindex]; ; p++) { p = (uintB*) strstr((char*)p,"var "); if (p == NULL) break; if ((strncmp((char*)p,"var object ", strlen("var object "))==0 || strncmp((char*)p,"var chart ", strlen("var chart "))==0) && (p[-1] == ' ' || p[-1] == '{')) { if (strncmp((char*)p,"var object ", strlen("var object "))==0) p += strlen("var object "); else if (strncmp((char*)p,"var chart ", strlen("var chart "))==0) p += strlen("var chart "); { uintB* q = p; if ((*q >= 'A' && *q <= 'Z') || (*q >= 'a' && *q <= 'z') || *q == '_') { do q++; while ((*q >= 'A' && *q <= 'Z') || (*q >= 'a' && *q <= 'z') || (*q >= '0' && *q <= '9') || *q == '_'); while (*q == ' ') q++; if (*q == '=') { uintL insertlen = 2+(q-p); if (out.buffindex + insertlen < MAXHEADERLEN) { memmove(q+insertlen,q, &out.buffer[out.buffindex]-q+1); q[0] = ';'; q[1] = ' '; memcpy(q+2, p, q-p); out.buffindex += insertlen; } } } } } } } } #endif } xfree(line); } goto separator; case '.': c = peek_char(); if (!(((c>='0') && (c<='9')) || (c=='.'))) goto separator; case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': /* Digit. Continue reading as long as alphanumeric or '.'. */ while (1) { c = peek_char(); if (((c>='0') && (c<='9')) || ((c>='A') && (c<='Z')) || ((c>='a') && (c<='z')) || (c=='.')) next_char(); else break; } token.type = number; goto done; case '\'': /* Character constant */ while (1) { c = next_char(); if (c==EOF) { fprintf(stderr,"Unterminated character constant\n"); break; } if (c=='\'') break; if (c=='\\') c = next_char(); } token.type = charconst; goto done; case '\"': /* String constant */ while (1) { c = next_char(); if (c==EOF) { fprintf(stderr,"Unterminated string constant\n"); break; } if (c=='\"') break; if (c=='\\') c = next_char(); } token.type = stringconst; goto done; case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G': case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z': case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g': case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n': case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u': case 'v': case 'w': case 'x': case 'y': case 'z': case '_': /* Identifier. */ while (1) { c = peek_char(); if (((c>='0') && (c<='9')) || ((c>='A') && (c<='Z')) || ((c>='a') && (c<='z')) || (c=='_')) next_char(); else break; } token.type = ident; goto done; default: separator: token.type = sep; token.ch = c; goto done; } } done: token.endindex = out.buffindex; return token; }
/////////////////////////////////////////////////////////////////// //eval //requires two arguments:exp & tail_context /////////////////////////////////////////////////////////////////// cellpoint eval(void) { if (is_true(is_self_evaluating(args_ref(1)))){ reg = args_ref(1); }else if (is_true(is_variable(args_ref(1)))){ reg = args_ref(1); args_push(current_env); args_push(reg); reg = lookup_var_val(); }else if (is_true(is_quoted(args_ref(1)))){ args_push(args_ref(1)); reg = quotation_text(); }else if (is_true(is_assignment(args_ref(1)))){ args_push(args_ref(1)); reg = eval_assignment(); }else if (is_true(is_definition(args_ref(1)))){ args_push(args_ref(1)); reg = eval_definition(); }else if (is_true(is_if(args_ref(1)))){ //eval if expression with the second argument (tail_context) reg = args_ref(1); args_push(args_ref(2)); args_push(reg); reg = eval_if(); }else if (is_true(is_lambda(args_ref(1)))){ args_push(args_ref(1)); reg = eval_lambda(); }else if (is_true(is_begin(args_ref(1)))){ args_push(args_ref(1)); reg = begin_actions(); //eval the actions of begin exp with the second argument (tail_context) args_push(args_ref(2)); args_push(reg); reg = eval_sequence(); }else if (is_true(is_cond(args_ref(1)))){ args_push(args_ref(1)); reg = cond_2_if(); //eval the exp with the second argument (tail_context) args_push(args_ref(2)); args_push(reg); reg = eval(); }else if (is_true(is_and(args_ref(1)))){ reg = args_ref(1); args_push(args_ref(2)); args_push(reg); reg = eval_and(); }else if (is_true(is_or(args_ref(1)))){ reg = args_ref(1); args_push(args_ref(2)); args_push(reg); reg = eval_or(); }else if (is_true(is_let(args_ref(1)))){ //convert let to combination args_push(args_ref(1)); reg = let_2_combination(); //evals the combination args_push(args_ref(2)); args_push(reg); reg = eval(); }else if (is_true(is_letstar(args_ref(1)))){ //convert let* to nested lets args_push(args_ref(1)); reg = letstar_2_nested_lets(); //evals the nested lets args_push(args_ref(2)); args_push(reg); reg = eval(); }else if (is_true(is_application(args_ref(1)))){ //computes operator args_push(args_ref(1)); reg = operator(); args_push(a_false); args_push(reg); reg = eval(); stack_push(&vars_stack, reg); //computes operands args_push(args_ref(1)); reg = operands(); args_push(reg); reg = list_of_values(); //calls apply with the second argument (tail_context) args_push(args_ref(2)); args_push(reg); args_push(stack_pop(&vars_stack)); reg = apply(); }else { printf("Unknown expression type -- EVAL\n"); error_handler(); } args_pop(2); return reg; }