objc/step4_if_fn_do.m

   1 #import <Foundation/Foundation.h>
   2
   3 #import "mal_readline.h"
   4 #import "types.h"
   5 #import "reader.h"
   6 #import "printer.h"
   7 #import "env.h"
   8 #import "malfunc.h"
   9 #import "core.h"
  10
  11 // read
  12 NSObject *READ(NSString *str) {
  13     return read_str(str);
  14 }
  15
  16 // eval
  17 NSObject *eval_ast(NSObject *ast, Env *env) {
  18     if ([ast isMemberOfClass:[MalSymbol class]]) {
  19         return [env get:(MalSymbol *)ast];
  20     } else if ([ast isKindOfClass:[NSArray class]]) {
  21         NSMutableArray *newLst = [NSMutableArray array];
  22         for (NSObject * x in (NSArray *)ast) {
  23             [newLst addObject:EVAL(x, env)];
  24         }
  25         if ([ast isKindOfClass:[MalVector class]]) {
  26             return [MalVector fromArray:newLst];
  27         } else {
  28             return newLst;
  29         }
  30     } else if ([ast isKindOfClass:[NSDictionary class]]) {
  31         NSMutableDictionary *newDict = [NSMutableDictionary dictionary];
  32         for (NSString * k in (NSDictionary *)ast) {
  33             newDict[k] = EVAL(((NSDictionary *)ast)[k], env);
  34         }
  35         return newDict;
  36     } else {
  37         return ast;
  38     }
  39 }
  40
  41 NSObject *EVAL(NSObject *ast, Env *env) {
  42     //NSLog(@"EVAL: %@ (%@)", _pr_str(ast, true), env);
  43     if (!list_Q(ast)) {
  44         return eval_ast(ast, env);
  45     }
  46
  47     NSArray * alst = (NSArray *)ast;
  48     id a0 = alst[0];
  49     NSString * a0sym = [a0 isKindOfClass:[MalSymbol class]] ? (NSString *)a0
  50                                                             : @"__<*fn*>__";
  51
  52     if ([a0sym isEqualTo:@"def!"]) {
  53         return [env set:((MalSymbol *)alst[1]) val:EVAL(alst[2], env)];
  54     } else if ([(NSString *)a0 isEqualTo:@"let*"]) {
  55         Env *let_env = [Env fromOuter:env];
  56         NSArray * binds = (NSArray *)alst[1];
  57         for (int i=0; i < [binds count]; i+=2) {
  58             [let_env set:binds[i] val:EVAL(binds[i+1], let_env)];
  59         }
  60         return EVAL(alst[2], let_env);
  61     } else if ([a0sym isEqualTo:@"do"]) {
  62         NSArray * el = (NSArray *)eval_ast(_rest(alst), env);
  63         return [el lastObject];
  64     } else if ([a0sym isEqualTo:@"if"]) {
  65         NSObject * cond = EVAL(alst[1], env);
  66         if ([cond isKindOfClass:[NSNull class]] ||
  67             [cond isKindOfClass:[MalFalse class]]) {
  68             if ([alst count] > 3) {
  69                 return EVAL(alst[3], env);
  70             } else {
  71                 return [NSNull alloc];
  72             }
  73         } else {
  74             return EVAL(alst[2], env);
  75         }
  76     } else if ([a0sym isEqualTo:@"fn*"]) {
  77         return [[MalFunc alloc] init:alst[2] env:env params:alst[1]];
  78     } else {
  79         NSArray * el = (NSArray *) eval_ast(ast, env);
  80         NSArray * args = @[];
  81         if ([el count] > 1) {
  82             args = _rest(el);
  83         }
  84         return apply(el[0], args);
  85         /*
  86         if ([el[0] isKindOfClass:[MalFunc class]]) {
  87             MalFunc * mf = el[0];
  88             return [mf apply:args];
  89         } else {
  90             NSObject * (^ f)(NSArray *) = el[0];
  91             return f(args);
  92         }
  93         */
  94     }
  95 }
  96
  97 // print
  98 NSString *PRINT(NSObject *exp) {
  99     return _pr_str(exp, true);
 100 }
 101
 102 // REPL
 103 NSString *REP(NSString *line, Env *env) {
 104     return PRINT(EVAL(READ(line), env));
 105 }
 106
 107 int main () {
 108     Env * repl_env = [[Env alloc] init];
 109
 110     // Create an autorelease pool to manage the memory into the program
 111     NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
 112     // If using automatic reference counting (ARC), use @autoreleasepool instead:
 113 //    @autoreleasepool {
 114
 115     // core.m: defined using Objective-C
 116     NSDictionary * core_ns = [Core ns];
 117     for (NSString* key in core_ns) {
 118         [repl_env set:(MalSymbol *)key val:[core_ns objectForKey:key]];
 119     }
 120
 121     // core.mal: defined using the language itself
 122     REP(@"(def! not (fn* (a) (if a false true)))", repl_env);
 123
 124     while (true) {
 125         char *rawline = _readline("user> ");
 126         if (!rawline) { break; }
 127         NSString *line = [NSString stringWithUTF8String:rawline];
 128         if ([line length] == 0) { continue; }
 129         @try {
 130             printf("%s\n", [[REP(line, repl_env) description] UTF8String]);
 131         } @catch(NSString *e) {
 132             printf("Error: %s\n", [e UTF8String]);
 133         } @catch(NSException *e) {
 134             if ([[e name] isEqualTo:@"ReaderContinue"]) { continue; }
 135             printf("Exception: %s\n", [[e reason] UTF8String]);
 136         }
 137     }
 138
 139     [pool drain];
 140
 141 //    }
 142 }