lisp/builtins.c

#include "lisp.h"

#define func_arithmetic_ex(name, operator, operator_name)                      \
    int name(Nodes *args, Scopes *scopes, Node *result) {                      \
        UNUSED(scopes);                                                        \
        if (args->count != 2) {                                                \
            puts("'" operator_name "' expects two arguments!\n");              \
            return 1;                                                          \
        }                                                                      \
        if (args->items[0].kind != NODE_KIND_NUMBER ||                         \
            args->items[1].kind != NODE_KIND_NUMBER) {                         \
            puts("'" operator_name                                             \
                 "' only works on numbers, you specified something "           \
                 "else!\n");                                                   \
            return 1;                                                          \
        }                                                                      \
        long long a = args->items[0].as_number;                                \
        long long b = args->items[1].as_number;                                \
        result->as_number = a operator b;                                      \
        result->kind = NODE_KIND_NUMBER;                                       \
        return 0;                                                              \
    }

#define func_arithmetic(name, operator)                                        \
    func_arithmetic_ex(name, operator, #operator)

func_arithmetic(lisp_function_add, +);
func_arithmetic(lisp_function_sub, -);
func_arithmetic(lisp_function_div, /);
func_arithmetic(lisp_function_mul, *);
func_arithmetic(lisp_function_mod, %);
func_arithmetic_ex(lisp_function_eq, ==, "=");
func_arithmetic(lisp_function_lt, <);
func_arithmetic(lisp_function_gt, >);
func_arithmetic(lisp_function_lt_eq, <=);
func_arithmetic(lisp_function_gt_eq, >=);

int lisp_function_println(Nodes *args, Scopes *scopes, Node *result) {
    if (args->count != 1) {
        printf("'+' expects one argument!\n");
        return 1;
    }

    eval_one(args->items[0], scopes, result);
    node_print(*result);
    printf("\n");

    return 0;
}

int lisp_function_list(Nodes *args, Scopes *scopes, Node *result) {
    UNUSED(scopes);

    result->kind = NODE_KIND_LIST;
    result->as_list = args;
    return 0;
}

int lisp_function_append(Nodes *args, Scopes *scopes, Node *result) {
    UNUSED(scopes);

    if (args->count != 2) {
        printf("'append' expects two arguments!\n");
        return 1;
    }

    if (args->items[0].kind != NODE_KIND_LIST ||
        args->items[1].kind != NODE_KIND_LIST) {
        printf("'append' can only append two lists!\n");
        return 1;
    }

    Nodes *nodes = malloc(sizeof(Nodes));
    memset(nodes, 0, sizeof(Nodes));

    Nodes *a = args->items[0].as_list;
    nob_da_append_many(nodes, a->items, a->count);

    Nodes *b = args->items[1].as_list;
    nob_da_append_many(nodes, b->items, b->count);

    result->as_list = nodes;
    result->kind = NODE_KIND_LIST;
    return 0;
}

int lisp_function_length(Nodes *args, Scopes *scopes, Node *result) {
    UNUSED(scopes);

    if (args->count != 1) {
        printf("'length' expects one argument!\n");
        return 1;
    }

    if (args->items[0].kind != NODE_KIND_LIST) {
        printf("'length' can only be used on lists!\n");
        return 1;
    }

    result->kind = NODE_KIND_NUMBER;
    result->as_number = args->items[0].as_list->count;
    return 0;
}

int lisp_function_isnull(Nodes *args, Scopes *scopes, Node *result) {
    UNUSED(scopes);

    if (args->count != 1) {
        printf("'null?' expects one argument!\n");
        return 1;
    }

    if (args->items[0].kind != NODE_KIND_LIST) {
        printf("'null?' can only be used on lists!\n");
        return 1;
    }

    result->kind = NODE_KIND_NUMBER;
    result->as_number = args->items[0].as_list->count == 0 ? 1 : 0;
    return 0;
}

int lisp_function_builtins(Nodes *args, Scopes *scopes, Node *result) {
    if (args->count != 0) {
        printf("'builtins' expects no arguments!\n");
        return 1;
    }

    Scope *global_scope = nob_da_first(scopes);
    Nodes *nodes = malloc(sizeof(Node));
    nob_da_foreach(ScopeObject, scope_object, global_scope) {
        nob_da_append(nodes, scope_object->node);
    }

    result->as_list = nodes;
    result->kind = NODE_KIND_LIST;
    return 0;
}