mal/c/stepA_more.c

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "types.h"
#include "readline.h"
#include "reader.h"
#include "interop.h"

// Declarations
MalVal *EVAL(MalVal *ast, Env *env);
MalVal *macroexpand(MalVal *ast, Env *env);

// read
MalVal *READ(char prompt[], char *str) {
    char *line;
    MalVal *ast;
    if (str) {
        line = str;
    } else {
        line = _readline(prompt);
        if (!line) {
            _error("EOF");
            return NULL;
        }
    }
    ast = read_str(line);
    if (!str) { free(line); }
    return ast;
}

// eval
int is_pair(MalVal *x) {
    return _sequential_Q(x) && (_count(x) > 0);
}

MalVal *quasiquote(MalVal *ast) {
    if (!is_pair(ast)) {
        return _list(2, malval_new_symbol("quote"), ast);
    } else {
        MalVal *a0 = _nth(ast, 0);
        if ((a0->type & MAL_SYMBOL) &&
            strcmp("unquote", a0->val.string) == 0) {
            return _nth(ast, 1);
        } else if (is_pair(a0)) {
            MalVal *a00 = _nth(a0, 0);
            if ((a00->type & MAL_SYMBOL) &&
                strcmp("splice-unquote", a00->val.string) == 0) {
                return _list(3, malval_new_symbol("concat"),
                                _nth(a0, 1),
                                quasiquote(rest(ast)));
            }
        }
        return _list(3, malval_new_symbol("cons"),
                        quasiquote(a0),
                        quasiquote(rest(ast)));
    }
}

int is_macro_call(MalVal *ast, Env *env) {
    if (!ast || ast->type != MAL_LIST) { return 0; }
    MalVal *a0 = _nth(ast, 0);
    return (a0->type & MAL_SYMBOL) &&
            env_find(env, a0->val.string) &&
            env_get(env, a0->val.string)->ismacro;
}
    
MalVal *macroexpand(MalVal *ast, Env *env) {
    if (!ast || mal_error) return NULL;
    while (is_macro_call(ast, env)) {
        MalVal *a0 = _nth(ast, 0);
        MalVal *mac = env_get(env, a0->val.string);
        // TODO: this is weird and limits it to 20. FIXME
        ast = apply(mac, rest(ast));
    }
    return ast;
}

MalVal *eval_ast(MalVal *ast, Env *env) {
    if (!ast || mal_error) return NULL;
    if (ast->type == MAL_SYMBOL) {
        //g_print("EVAL symbol: %s\n", ast->val.string);
        return env_get(env, ast->val.string);
    } else if ((ast->type == MAL_LIST) || (ast->type == MAL_VECTOR)) {
        //g_print("EVAL sequential: %s\n", _pr_str(ast,1));
        MalVal *el = _map2((MalVal *(*)(void*, void*))EVAL, ast, env);
        if (!el || mal_error) return NULL;
        el->type = ast->type;
        return el;
    } else if (ast->type == MAL_HASH_MAP) {
        //g_print("EVAL hash_map: %s\n", _pr_str(ast,1));
        GHashTableIter iter;
        gpointer key, value;
        MalVal *seq = malval_new_list(MAL_LIST,
                                    g_array_sized_new(TRUE, TRUE, sizeof(MalVal*),
                                                        _count(ast)));
        g_hash_table_iter_init (&iter, ast->val.hash_table);
        while (g_hash_table_iter_next (&iter, &key, &value)) {
            MalVal *kname = malval_new_string((char *)key);
            g_array_append_val(seq->val.array, kname);
            MalVal *new_val = EVAL((MalVal *)value, env);
            g_array_append_val(seq->val.array, new_val);
        }
        return hash_map(seq);
    } else {
        //g_print("EVAL scalar: %s\n", _pr_str(ast,1));
        return ast;
    }
}

MalVal *EVAL(MalVal *ast, Env *env) {
    while (TRUE) {
        if (!ast || mal_error) return NULL;
        //g_print("EVAL: %s\n", _pr_str(ast,1));
        if (ast->type != MAL_LIST) {
            return eval_ast(ast, env);
        }
        if (!ast || mal_error) return NULL;

        // apply list
        //g_print("EVAL apply list: %s\n", _pr_str(ast,1));
        ast = macroexpand(ast, env);
        if (!ast || mal_error) return NULL;
        if (ast->type != MAL_LIST) { return ast; }
        if (_count(ast) == 0) { return ast; }

        int i, len;
        MalVal *a0 = _nth(ast, 0);
        if ((a0->type & MAL_SYMBOL) &&
            strcmp("def!", a0->val.string) == 0) {
            //g_print("eval apply def!\n");
            MalVal *a1 = _nth(ast, 1),
                   *a2 = _nth(ast, 2);
            MalVal *res = EVAL(a2, env);
            env_set(env, a1->val.string, res);
            return res;
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("let*", a0->val.string) == 0) {
            //g_print("eval apply let*\n");
            MalVal *a1 = _nth(ast, 1),
                   *a2 = _nth(ast, 2),
                   *key, *val;
            assert_type(a1, MAL_LIST|MAL_VECTOR,
                        "let* bindings must be list or vector");
            len = _count(a1);
            assert((len % 2) == 0, "odd number of let* bindings forms");
            Env *let_env = new_env(env, NULL, NULL);
            for(i=0; i<len; i+=2) {
                key = g_array_index(a1->val.array, MalVal*, i);
                val = g_array_index(a1->val.array, MalVal*, i+1);
                assert_type(key, MAL_SYMBOL, "let* bind to non-symbol");
                env_set(let_env, key->val.string, EVAL(val, let_env));
            }
            return EVAL(a2, let_env);
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("quote", a0->val.string) == 0) {
            //g_print("eval apply quote\n");
            return _nth(ast, 1);
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("quasiquote", a0->val.string) == 0) {
            //g_print("eval apply quasiquote\n");
            MalVal *a1 = _nth(ast, 1);
            return EVAL(quasiquote(a1), env);
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("defmacro!", a0->val.string) == 0) {
            //g_print("eval apply defmacro!\n");
            MalVal *a1 = _nth(ast, 1),
                   *a2 = _nth(ast, 2);
            MalVal *res = EVAL(a2, env);
            res->ismacro = TRUE;
            env_set(env, a1->val.string, res);
            return res;
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("macroexpand", a0->val.string) == 0) {
            //g_print("eval apply macroexpand\n");
            MalVal *a1 = _nth(ast, 1);
            return macroexpand(a1, env);
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp(".", a0->val.string) == 0) {
            //g_print("eval apply .\n");
            MalVal *el = eval_ast(_slice(ast, 1, _count(ast)), env);
            return invoke_native(el);
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("try*", a0->val.string) == 0) {
            //g_print("eval apply try*\n");
            MalVal *a1 = _nth(ast, 1);
            MalVal *a2 = _nth(ast, 2);
            MalVal *res = EVAL(a1, env);
            if (!mal_error) { return res; }
            MalVal *a20 = _nth(a2, 0);
            if (strcmp("catch*", a20->val.string) == 0) {
                MalVal *a21 = _nth(a2, 1);
                MalVal *a22 = _nth(a2, 2);
                Env *catch_env = new_env(env,
                                         _list(1, a21),
                                         _list(1, mal_error));
                //malval_free(mal_error);
                mal_error = NULL;
                res = EVAL(a22, catch_env);
                return res;
            } else {
                return &mal_nil;
            }
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("do", a0->val.string) == 0) {
            //g_print("eval apply do\n");
            eval_ast(_slice(ast, 1, _count(ast)-1), env);
            ast = last(ast);
            // Continue loop
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("if", a0->val.string) == 0) {
            //g_print("eval apply if\n");
            MalVal *a1 = _nth(ast, 1);
            MalVal *cond = EVAL(a1, env);
            if (!cond || mal_error) return NULL;
            if (cond->type & (MAL_FALSE|MAL_NIL)) {
                // eval false slot form
                ast = _nth(ast, 3);
                if (!ast) {
                    return &mal_nil;
                }
            } else {
                // eval true slot form
                ast = _nth(ast, 2);
            }
            // Continue loop
        } else if ((a0->type & MAL_SYMBOL) &&
                   strcmp("fn*", a0->val.string) == 0) {
            //g_print("eval apply fn*\n");
            MalVal *mf = malval_new(MAL_FUNCTION_MAL, NULL);
            mf->ismacro = FALSE;
            mf->val.func.evaluator = EVAL;
            mf->val.func.args = _nth(ast, 1);
            mf->val.func.body = _nth(ast, 2);
            mf->val.func.env = env;
            return mf;
        } else {
            //g_print("eval apply\n");
            MalVal *el = eval_ast(ast, env);
            if (!el || mal_error) { return NULL; }
            MalVal *f = first(el),
                   *args = rest(el);
            assert_type(f, MAL_FUNCTION_C|MAL_FUNCTION_MAL,
                        "cannot invoke '%s'", _pr_str(f,1));
            if (f->type & MAL_FUNCTION_MAL) {
                ast = f->val.func.body;
                env = new_env(f->val.func.env, f->val.func.args, args);
                // Continue loop
            } else {
                return apply(f, args);
            }
        }
    }
}
    
// print
char *PRINT(MalVal *exp) {
    if (mal_error) {
        fprintf(stderr, "Error: %s\n", mal_error->val.string);
        malval_free(mal_error);
        mal_error = NULL;
        return NULL;
    }
    return _pr_str(exp,1);
}

// repl

// read and eval
MalVal *RE(Env *env, char *prompt, char *str) {
    MalVal *ast, *exp;
    ast = READ(prompt, str);
    if (!ast || mal_error) return NULL;
    exp = EVAL(ast, env);
    if (ast != exp) {
        malval_free(ast);    // Free input structure
    }
    return exp;
}

// Setup the initial REPL environment
Env *repl_env;

char *slurp_raw(char *path) {
    char *data;
    struct stat fst;
    int fd = open(path, O_RDONLY),
        sz;
    if (fd < 0) {
        abort("slurp failed to open '%s'", path);
    }
    if (fstat(fd, &fst) < 0) {
        abort("slurp failed to stat '%s'", path);
    }
    data = malloc(fst.st_size+1);
    sz = read(fd, data, fst.st_size);
    if (sz < fst.st_size) {
        abort("slurp failed to read '%s'", path);
    }
    data[sz] = '\0';
    return data;
}

void init_repl_env() {
    void _ref(char *name, MalVal*(*func)(MalVal*), int arg_cnt) {
        void *(*f)(void *) = (void*(*)(void*))func;
        env_set(repl_env, name, malval_new_function(f, arg_cnt, NULL));
    }
    repl_env = new_env(NULL, NULL, NULL);

    int i;
    for(i=0; i< (sizeof(types_ns) / sizeof(types_ns[0])); i++) {
        MalVal *(*f)(MalVal *) = (MalVal*(*)(MalVal*))types_ns[i].func;
        _ref(types_ns[i].name, f, types_ns[i].arg_cnt);
    }

    MalVal *readline(MalVal *str) {
        assert_type(str, MAL_STRING, "readline of non-string");
        char * line = _readline(str->val.string);
        if (line) { return malval_new_string(line); }
        else      { return &mal_nil; }
    }
    _ref("readline", readline, 1);

    MalVal *read_string(MalVal *str) {
        assert_type(str, MAL_STRING, "read_string of non-string");
        return read_str(str->val.string);
    }
    _ref("read-string", read_string, 1);

    MalVal *do_eval(MalVal *ast) {
        return EVAL(ast, repl_env);
    }
    _ref("eval", do_eval, 1);

    MalVal *slurp(MalVal *path) {
        assert_type(path, MAL_STRING, "slurp of non-string");
        char *data = slurp_raw(path->val.string);
        if (!data || mal_error) { return NULL; }
        return malval_new_string(data);
    }
    _ref("slurp", slurp, 1);

    RE(repl_env, "", "(def! not (fn* (a) (if a false true)))");
    RE(repl_env, "", "(defmacro! cond (fn* (& xs) (if (> (count xs) 0) (list 'if (first xs) (if (> (count xs) 1) (nth xs 1) (throw \"odd number of forms to cond\")) (cons 'cond (rest (rest xs)))))))");
    RE(repl_env, "", "(defmacro! or (fn* (& xs) (if (empty? xs) nil (if (= 1 (count xs)) (first xs) `(let* (or_FIXME ~(first xs)) (if or_FIXME or_FIXME (or ~@(rest xs))))))))");
    RE(repl_env, "",
       "(def! load-file (fn* (f) (eval (read-string (str \"(do \" (slurp f) \")\")))))");
}

int main(int argc, char *argv[])
{
    MalVal *exp;
    char *output;
    char prompt[100];

    // Set the initial prompt and environment
    snprintf(prompt, sizeof(prompt), "user> ");
    init_repl_env();
 
    if (argc > 1) {
        char *cmd = g_strdup_printf("(load-file \"%s\")", argv[1]);
        RE(repl_env, "", cmd);
    } else {
        // REPL loop
        for(;;) {
            exp = RE(repl_env, prompt, NULL);
            if (mal_error && strcmp("EOF", mal_error->val.string) == 0) {
                return 0;
            }
            output = PRINT(exp);

            if (output) { 
                g_print("%s\n", output);
                free(output);        // Free output string
            }

            //malval_free(exp);    // Free evaluated expression
        }
    }
}