pebblisp/src/pebblisp.c

#include "pebblisp.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <readline/readline.h>
#include <readline/history.h>

#include "tokens.h"
#ifdef STANDALONE
#include "web.h"
#endif

/**
 * Inserts a variable into the environment with a given name and value.
 *
 * If `argForms` (symbol) and `argForms->forward` (value) are lists of the same
 * length, define each symbol element with the corresponding value element.
 * I.e. `(def (a b) (5 20))` would store `a` as `5` and `b` as `20`.
 *
 * @param argForms The symbol(s) and value(s) to define in the environment
 * @param env The environment to add the new definition to
 * @return The symbol(s) defined
 */
Object evalDefArgs(const Object* symbol, const Object* value,
                   struct Environment* env)
{
    const char* name = symbol->string;

    // Handles multi-definitions
    if (bothAre(TYPE_LIST, symbol, value) &&
        listLength(symbol) == listLength(value)) {
        FOR_POINTERS_IN_LISTS(symbol, value) {
            Object finalValue = eval(P2, env);
            addToEnv(env, P1->string, finalValue);
            cleanObject(&finalValue);
        }
        return cloneObject(*symbol);
    }

    Object finalValue = eval(value, env);

    addToEnv(env, name, finalValue);
    cleanObject(&finalValue);

    return cloneObject(*symbol);
}

void printStructDef(const struct StructDef *def)
{
    printf("%s: {\n", def->name);
    for (int i = 0; i < def->fieldCount; i++) {
        printf("  %s,\n", def->names[i]);
    }
    printf("}\n");
}

/**
 * Add a struct to the environment with a given name and fields.
 *
 * (struct point (x y))
 */
Object evalStructArgs(const Object* symbol, const Object* fields, struct Environment* env)
{
    const char* name = symbol->string;

    if (!isListy(*fields)) {
        return errorObject(NOT_A_LIST);
    }

    struct StructDef def;
    //def.name = name;
    def.name = malloc(sizeof(char) * (strlen(name) + 1));
    strcpy(def.name, name);
    def.fieldCount = listLength(fields);
    def.names = malloc(sizeof(char*) * def.fieldCount);

    int i = 0;
    FOR_POINTER_IN_LIST(fields) {
        def.names[i] = malloc(sizeof(char) * (strlen(POINTER->string) + 1));
        strcpy(def.names[i], POINTER->string);
        i++;
    }

    while (env->outer) {
        env = env->outer;
    }

    env->structDefs[env->structCount] = def;
    //printStructDef(&env->structDefs[env->structCount]);
    env->structCount += 1;
    if (env->structCount == env->structCapacity) {
        struct StructDef* prev = env->structDefs;
        int prevCapacity = env->structCapacity;
        env->structCapacity *= 2;
        env->structDefs = malloc(sizeof(struct StructDef) * env->structCapacity);
        printf("Can malloc\n");
        //memcpy(env->structDefs, prev, sizeof(struct StructDef) * prevCapacity);
        //printf("Can memcpy\n");
        for (int i = 0; i < prevCapacity; i++) {
            env->structDefs[i] = prev[i];
        }
        free(prev);
    }

    return boolObject(1);
}

Object evalIfArgs(const Object* argForms, struct Environment* env)
{
    Object condition = eval(argForms, env);
    Object result = condition.number ? eval(argForms->forward, env)
                                     : eval(argForms->forward->forward, env);
    cleanObject(&condition);
    return result;
}

Object evalLambdaArgs(const Object* argForms)
{
    return constructLambda(argForms,                          // Params
                           argForms ? argForms->forward : NULL  // Body
    );
}

Object evalMapArgs(const Object* argForms, struct Environment* env)
{
    if (!argForms) {
        return errorObject(NULL_MAP_ARGS);
    }

    Object lambda = eval(argForms, env);
    const Object* inputList = argForms->forward;
    Object outputList = listObject();

    if (lambda.type != TYPE_LAMBDA) {
        return errorObject(BAD_TYPE);
    }

    if (inputList) {
        FOR_POINTER_IN_LIST(inputList) {
            // Create a new list for each element,
            // since lambda evaluation looks for a list
            Object tempList = startList(cloneObject(*POINTER));

            Object* params = &lambda.lambda->params;
            struct Environment newEnv = envForLambda(params, &tempList, env);

            // Add the lambda evaluation to the list
            Object lambda_output = eval(&lambda.lambda->body, &newEnv);
            Object delisted = cloneObject(*lambda_output.list);
            nf_addToList(&outputList, delisted);
            deleteEnv(&newEnv);
            cleanObject(&tempList);
            cleanObject(&lambda_output);
        }
    }
    cleanObject(&lambda);

    return outputList;
}

Object evalBuiltIns(const Object* first, const Object* rest,
                    struct Environment* env)
{
    if (first->type != TYPE_SYMBOL) {
        return errorObject(NOT_A_SYMBOL);
    }

    if (strcmp(first->string, "def") == 0) {
        return evalDefArgs(rest, rest->forward, env);
#ifndef LOW_MEM
    } else if (strcmp(first->string, "defe") == 0) {
        Object symbol = eval(rest, env);
        Object e = evalDefArgs(&symbol, rest->forward, env);
        cleanObject(&symbol);
        return e;
#endif
    } else if (strcmp(first->string, "if") == 0) {
        return evalIfArgs(rest, env);
    } else if (strcmp(first->string, "fn") == 0) {
        return evalLambdaArgs(rest);
    } else if (strcmp(first->string, "map") == 0) {
        return evalMapArgs(rest, env);
    } else if (strcmp(first->string, "struct") == 0) {
        return evalStructArgs(rest, rest->forward, env);
    }

    return errorObject(BUILT_IN_NOT_FOUND);
}

/**
 * Bulk evaluator of Objects in a given list. Puts the results in a given array
 *
 * Note that `destArr` is a raw array, not an Object list, and that `start` is
 * not itself a list, but the first element *in* a list to be evaluated. This
 * allows more speed and flexibility in what should be evaluated.
 *
 * @param destArr The raw array to put the results into. Not an Object list!
 * @param start The Object element to start with
 * @param env The environment to use while evaluating
 */
void evalForms(Object* destArr, const Object* start, struct Environment* env)
{
    int i = 0;
    while (start) {
        destArr[i] = eval(start, env);
        start = start->forward;
        i++;
    }
}

/**
 * Evaluates a list whose first element is a function, applying that function
 *
 * Tries to either apply the function to its parameters, or create a partial
 * function, if not enough parameters were passed.
 *
 * @param list The list being evaluated
 * @param function First element of the list, already evaluated to be a function
 * @param length Length of `list` - 1, to exclude the already-evaluated element
 * @param env The environment to evaluate in
 */
Object listEvalFunc(const Object* list, const Object* function,
                    const int length, struct Environment* env)
{
    if (length == 0) {
        return function->func(boolObject(0), boolObject(0), env);
    }

    Object rest[length];
    evalForms(rest, list->list->forward, env);

    Object func_result = rest[0];
    if (length == 1) {
        Object oneArg = errorObject(ONLY_ONE_ARGUMENT);
        func_result = function->func(func_result, oneArg, env);
        // Return a partial function if more parameters are required
        // Otherwise, return the function result
        cleanObject(&rest[0]);
        if (isError(func_result, ONLY_ONE_ARGUMENT)) {
            // These functions modify their second argument,
            // so we don't clean oneArg here
            cleanObject(&func_result);
            return cloneObject(*list);
        } else {
            cleanObject(&oneArg);
            return func_result;
        }
    } else {
        // With two args, will apply function once
        // With more than two args, apply the function repeatedly
        for (int i = 1; i < length; i++) {
            Object toClean = func_result;
            func_result = function->func(func_result, rest[i], env);
            cleanObject(&toClean);
            cleanObject(&rest[i]);
        }
        return func_result;
    }
}

/**
 * Evaluates a list whose first element is a lambda, applying that lambda
 *
 * Tries to apply the lambda to its parameters. Doesn't attempt partial
 * application.
 *
 * @param lambda First element of the list, already evaluated to be a lambda
 * @param remaining The first element after `lambda`
 * @param env The environment to evaluate in
 */
Object listEvalLambda(Object* lambda, const Object* remaining,
                      struct Environment* env)
{
    struct Environment newEnv =
        envForLambda(&lambda->lambda->params, remaining, env);
    Object ret = eval(&lambda->lambda->body, &newEnv);

    deleteEnv(&newEnv);
    cleanObject(lambda);

    Object* t = tail(&ret);
    if (t) {
        Object o = cloneObject(*t);
        cleanObject(&ret);
        return o;
    }
    return ret;
}

/**
 * Evaluates a given list, including the application of functions and lambdas
 *
 * Engages in several behaviors, depending on list contents:
 * - () => ()
 * - (x y z) => (eval_x eval_y eval_z)
 * - (function x y) => evaluated function(x, y)
 * - (function ...) => evaluated function(...) applied to each arg
 * - (function x) => functionx() partial function
 * - (lambda x) => evaluated lambda(x)
 *
 * @param obj The list to be evaluated
 * @param env The environment to evaluate in
 */
Object evalList(const Object* obj, struct Environment* env)
{
    const int evalLength = listLength(obj);

    if (evalLength == 0) {
        return cloneObject(*obj);
    }

    Object* first_form = obj->list;
    {    // Try to eval built-ins
        Object builtIn = evalBuiltIns(first_form, first_form->forward, env);

        if (!isError(builtIn, BUILT_IN_NOT_FOUND) &&
            !isError(builtIn, NOT_A_SYMBOL)) {
            return builtIn;
        }
        cleanObject(&builtIn);
    }

    //struct StructDef *def = NULL;
    int def = -1;
    if (first_form->type == TYPE_SYMBOL) {
        struct Environment* outerEnv = env;
        while (outerEnv->outer) {
            outerEnv = outerEnv->outer;
        }
        //printf("evalList firstElementName: %s\n", first_form->string);
        //printf("checking for struct `%s`\n", first_form->string);
        //printf("%d structs available\n", outerEnv->structCount);
        for (int i = 0; i < outerEnv->structCount; i++) {
            //printf("struct[%d] - `%s`\n", i, outerEnv->structDefs[i].name);
            if (strcmp(first_form->string, outerEnv->structDefs[i].name) == 0) {
                def = i;
                //printf("Found struct definition for %s!\n", first_form->string);
                break;
            }
        }
    }
    if (def >= 0) {
        Object structo = structObject(def);
        int i = 0;
        FOR_POINTER_IN_LIST(obj) {
            if (i != 0) {
                structo.structObject->fields[i - 1] = eval(POINTER, env);
            }
            i++;
        }
        return structo;
    }

    // Evaluate the list based on the first element's type
    Object first_eval = eval(first_form, env);
    switch (first_eval.type) {
        case TYPE_FUNC:
            // Passes evalLength - 1, because we skip the first form
            return listEvalFunc(obj, &first_eval, evalLength - 1, env);

        case TYPE_LAMBDA:
            return listEvalLambda(&first_eval, first_form->forward, env);

        default: {    // Return list with each element evaluated
            Object list = listObject();
            int i = 0;
            nf_addToList(&list, first_eval);
            FOR_POINTER_IN_LIST(obj) {
                if (i != 0) {
                    nf_addToList(&list, eval(POINTER, env));
                }
                i++;
            }
            return list;
        }
    }
}

Object eval(const Object* obj, struct Environment* env)
{
    switch (obj->type) {
        case TYPE_FUNC:
        case TYPE_ERROR:
        case TYPE_OTHER:
        case TYPE_NUMBER:
        case TYPE_BOOL:
        case TYPE_STRING:
        case TYPE_STRUCT:
            return cloneObject(*obj);

        case TYPE_SYMBOL:
            return fetchFromEnvironment(obj->string, env);

        case TYPE_SLIST: {
            Object o = cloneObject(*obj);
            o.type = TYPE_LIST;
            return o;
        }

        case TYPE_LIST:
            return evalList(obj, env);

        case TYPE_LAMBDA:
            return eval(&obj->lambda->body, env);
    }

    return errorObject(BAD_TYPE);
}

#define CAT_MAX 1024
Object catObjects(const Object obj1, const Object obj2, struct Environment* env)
{
    Object evalObj1 = eval(&obj1, env);
    Object evalObj2 = eval(&obj2, env);

    char str1[CAT_MAX] = "";
    char str2[CAT_MAX] = "";
    stringObj(str1, &evalObj1);
    stringObj(str2, &evalObj2);
    cleanObject(&evalObj1);
    cleanObject(&evalObj2);
    int length = strlen(str1) + strlen(str2) + 1;

    Object o = newObject(TYPE_STRING);
    o.string = calloc(sizeof(char), length);
    strcat(o.string, str1);
    strcat(o.string, str2);

    return o;
}

Object listEquality(const Object* list1, const Object* list2)
{
    FOR_POINTERS_IN_LISTS(list1, list2) {
        if (P1->type != P2->type || P1->number != P2->number) {
            return boolObject(0);
        }
    }
    return boolObject(1);
}

Object _basicOp(const Object* obj1, const Object* obj2, const char op,
                struct Environment* env)
{
    const int n1 = obj1->number;
    const int n2 = obj2->number;

    switch (op) {
        case '+':
            if (eitherIs(TYPE_STRING, obj1, obj2)) {
                return catObjects(*obj1, *obj2, env);
            }
            return numberObject(n1 + n2);
        case '-':
            return numberObject(n1 - n2);
        case '*':
            return numberObject(n1 * n2);
        case '/':
            return numberObject(n1 / n2);
        case '%':
            return numberObject(n1 % n2);

        case '&':
            return boolObject(n1 != 0 && n2 != 0);
        case '|':
            return boolObject(n1 != 0 || n2 != 0);

        case '=':
            if (bothAre(TYPE_STRING, obj1, obj2)) {
                return boolObject(!strcmp(obj1->string, obj2->string));
            }
            if (bothAre(TYPE_LIST, obj1, obj2)) {
                return listEquality(obj1, obj2);
            }
            return boolObject(n1 == n2 && areSameType(obj1, obj2));
        case '>':
            return boolObject(n1 > n2);
        case '<':
            return boolObject(n1 < n2);
    }

    return *obj1;
}

Object basicOp(const Object* obj1, const Object* obj2, const char op,
               struct Environment* env)
{
    if (isError(*obj2, ONLY_ONE_ARGUMENT)) {
        return *obj2;
    }

    int lists = (obj1->type == TYPE_LIST) + (obj2->type == TYPE_LIST);
    if (lists == 0) {
        return _basicOp(obj1, obj2, op, env);

    } else if (lists ==
               1) {    // Single operand is applied to each element in list
        const Object* listObj = (obj1->type == TYPE_LIST) ? obj1 : obj2;
        const Object* singleObj = (obj1->type == TYPE_LIST) ? obj2 : obj1;

        Object newList = listObject();
        FOR_POINTER_IN_LIST(listObj) {
            Object adding = eval(POINTER, env);
            nf_addToList(&newList, _basicOp(&adding, singleObj, op, env));
        }
        return newList;

    } else {    // 2 lists with the op applied to matching indices of both lists
        if (listLength(obj1) == listLength(obj2)) {
            Object newList = listObject();
            FOR_POINTERS_IN_LISTS(obj1, obj2) {
                const Object ev1 = eval(P1, env);
                const Object ev2 = eval(P2, env);
                nf_addToList(&newList, _basicOp(&ev1, &ev2, op, env));
            }
            return newList;
        } else {
            return errorObject(LISTS_NOT_SAME_SIZE);
        }
    }
}

#define BASIC_OP(_name, _char)                                      \
    Object _name(Object obj1, Object obj2, struct Environment *env) \
    {                                                               \
        return basicOp(&obj1, &obj2, _char, env);                   \
    }

BASIC_OP(add, '+');

BASIC_OP(sub, '-');

BASIC_OP(mul, '*');

BASIC_OP(dvi, '/');

BASIC_OP(mod, '%');

BASIC_OP(equ, '=');

BASIC_OP(gth, '>');

BASIC_OP(lth, '<');

BASIC_OP(and, '&');

BASIC_OP(or, '|');

#undef BASIC_OP

Object filter(Object obj1, Object obj2, struct Environment* env)
{
    Object filteredList = listObject();
    Object* filteringList = &obj2;
    FOR_POINTER_IN_LIST(filteringList) {
        Object conditional = cloneObject(obj1);
        nf_addToList(&conditional, *POINTER);    // cloneObject()?
        Object result = eval(&conditional, env);
        cleanObject(&conditional);
        if (result.number == 1) {
            nf_addToList(&filteredList, *POINTER);
        }
    }
    return filteredList;
}

Object append(Object list, Object newElement, struct Environment* env)
{
    Object newList = cloneObject(list);
    nf_addToList(&newList, cloneObject(newElement));
    return newList;
}

Object prepend(Object list, Object newElement, struct Environment* env)
{
    Object newList = listObject();
    nf_addToList(&newList, cloneObject(newElement));
    appendList(&newList, &list);
    return newList;
}

Object at(Object index, Object list, struct Environment* env)
{
    const Object* found = itemAt(&list, index.number);
    if (found) {
        return cloneObject(*found);
    } else {
        return errorObject(INDEX_PAST_END);
    }
}

Object rest(Object list, Object ignore, struct Environment* env)
{
    Object ret = listObject();
    Object* l = &list;
    FOR_POINTER_IN_LIST(l) {
        if (POINTER == l->list) {
            continue;
        }
        nf_addToList(&ret, cloneObject(*POINTER));
    }
    return ret;
}

Object reverse(Object _list, Object ignore, struct Environment* ignore2)
{
    const Object* list = &_list;
    Object rev = listObject();

    Object* tail = NULL;
    FOR_POINTER_IN_LIST(list) {
        Object* oldTail = tail;
        allocObject(&tail, cloneObject(*POINTER));
        if (oldTail) {
            tail->forward = oldTail;
        }
    }

    rev.list = tail;
    return rev;
}

Object isNum(Object test, Object ignore, struct Environment* ignore2)
{
    return test.type == TYPE_NUMBER ? boolObject(1) : boolObject(0);
}

Object isString(Object test, Object ignore, struct Environment* ignore2)
{
    return test.type == TYPE_STRING ? boolObject(1) : boolObject(0);
}

// Get the int value of a string's first character
Object charVal(Object test, Object ignore, struct Environment* ignore2)
{
    return numberObject(test.string[0]);
    //    return test.type == TYPE_STRING && test.string[0] == '\0' ?
    //        boolObject(1) : boolObject(0);
}

Object isErr(Object test, Object ignore, struct Environment* ignore2)
{
    return test.type == TYPE_ERROR ? boolObject(1) : boolObject(0);
}

Object charAt(Object string, Object at, struct Environment* ignore)
{
    char* c = malloc(sizeof(char) * 2);
    c[0] = string.string[at.number];
    c[1] = '\0';
    string.string = c;
    return string;
}

#ifdef STANDALONE

Object print(Object p, Object ignore, struct Environment* env)
{
    p = cloneObject(p);
    p = eval(&p, env);
    _printObj(&p, 0);
    return numberObject(0);
}

Object addRouteO(Object path, Object textFunc, struct Environment* env)
{
    char* p = malloc(sizeof(char) * strlen(path.string) + 1);
    strcpy(p, path.string);
    //const char* t = malloc(sizeof(char) * strlen(textFunc.string) + 1);
    //strcpy(t, textFunc.string);

    struct Route r;
    r.path = p;
    r.routeAction = cloneObject(textFunc);
    r.env = env;
    env->refs += 1;
    //r.text = t;
    addRoute(r);

    return numberObject(1);
}

Object startServer(Object portObject, Object ignored, struct Environment* env)
{
    int port = 8888;
    if (portObject.type == TYPE_NUMBER) {
        port = portObject.number;
    }
    return numberObject(start(port));
}

Object pChar(Object c, Object i1, struct Environment* i2)
{
    if (c.type != TYPE_NUMBER) {
        return errorObject(BAD_NUMBER);
    }
    printf("%c", c.number % 256);
    return numberObject(0);
}

Object printEnvO(Object i1, Object i2, struct Environment* env)
{
    while (env->outer) {
        env = env->outer;
    }

    printEnv(env);
    return numberObject(0);
}

#endif

Object parseEvalO(Object text, Object ignore, struct Environment* env)
{
    if (text.type == TYPE_SYMBOL) {
        Object string = eval(&text, env);
        Object parsed = parseEval(string.string, env);
        cleanObject(&string);
        return parsed;
    } else if (text.type != TYPE_STRING) {
        return errorObject(CAN_ONLY_EVAL_STRINGS);
    }
    return parseEval(text.string, env);
}

#ifdef STANDALONE

Object takeInput(Object i1, Object i2, struct Environment* i3)
{
    char input[256] = "";
    fgets(input, 256, stdin);
    return stringFromSlice(input, strlen(input) - 1);
}

#endif

void copySlice(char* dest, struct Slice* src)
{
    if (!dest || !src) {
        return;
    }
    strncpy(dest, src->text, src->length);
    dest[(int) src->length] = '\0';
}

void debugSlice(struct Slice* s)
{
#ifdef DEBUG
    if (!s) {
        printf("NULL SLICE\n");
        return;
    }
    printf("Debug Slice\n    text:'");
    for (int i = 0; i < s->length; i++) {
        printf("%c", s->text[i]);
        if (s->text[i] == '\0') {
            printf("NULLCHAR\n");
        }
    }
    printf("'\n");
    printf("  length: %d\n", s->length);
#endif
}

Object possessive(Object structo, Object field, struct Environment* env)
{
    if (structo.type != TYPE_STRUCT) {
        printf("`'s` must be used on a struct!\n");
        return errorObject(NULL_PARSE);
    }
    if (!isStringy(field)) {
        printf("`'s` field name must be stringy! Received a ");
        printType(&field);
        printObj(&field);
        printf("\n");
        return errorObject(NULL_PARSE);
    }

    struct StructDef structDef = global()->structDefs[structo.structObject->definition];
    for (int i = 0; i < structDef.fieldCount; i++) {
        if (strcmp(field.string, structDef.names[i]) == 0) {
            return cloneObject(structo.structObject->fields[i]);
        }
    }

    printf("Could not find field name `%s`\n", field.string);
    return errorObject(NULL_PARSE);
}

Result parse(struct Slice* slices)
{
    struct Slice* token = slices;
    if (token && token->text) {
        struct Slice* rest = &slices[1];
        if (token->text[0] == '\'' && token->text[1] == '(') {
            Result r = readSeq(&slices[2]);
            r.obj.type = TYPE_SLIST;
            return r;
        } else if (token->text[0] == '(') {
            // todo check for null rest
            return readSeq(rest);
        } else {    // todo error on missing close paren
            Result r = parseAtom(token);
            r.slices = &r.slices[1];
            return r;
        }
    } else {
        return (Result) {errorObject(NULL_PARSE), NULL};
    }
}

Result readSeq(struct Slice* tokens)
{
    Object res = listObject();
    for (;;) {
        struct Slice* next = tokens;
        struct Slice* rest = next->text ? &next[1] : NULL;
        if (next->text[0] == ')') {
            return (Result) {res, rest};
        }
        Result r = parse(tokens);
        if (r.obj.type == TYPE_ERROR) {
            return r;
        }
        nf_addToList(&res, cloneObject(r.obj));
        tokens = r.slices;
        cleanObject(&r.obj);
    }
}

Object parseDecimal(struct Slice* s)
{
    int num = 0;
    for (int i = 0; i < s->length; i++) {
        if (!isDigit(s->text[i])) {
            return errorObject(BAD_NUMBER);
        }
        num *= 10;
        num += s->text[i] - '0';
    }
    return numberObject(num);
}

Object parseHex(struct Slice* s)
{
    int num = 0;
    for (int i = 2; i < s->length; i++) {
        const char c = s->text[i];
        if (!isHex(c)) {
            return errorObject(BAD_NUMBER);
        }
        num *= 16;
        if (isDigit(c)) {
            num += c - '0';
        } else /* is hex */ {
            num += c - 'a' + 10;
        }
    }
    return numberObject(num);
}

Object parseBin(struct Slice* s)
{
    int num = 0;
    for (int i = 2; i < s->length; i++) {
        const char c = s->text[i];
        if (c != '0' && c != '1') {
            return errorObject(BAD_NUMBER);
        }
        num *= 2;
        num += c - '0';
    }
    return numberObject(num);
}

Result parseAtom(struct Slice* s)
{
    const char c = s->text[0];
    if (isDigit(c)) {
        if (c != '0' || s->length == 1) {
            return (Result) {parseDecimal(s), s};
#ifndef LOW_MEM
        } else if (c == '0' && s->text[1] == 'x') {
            return (Result) {parseHex(s), s};
        } else if (c == '0' && s->text[1] == 'b') {
            return (Result) { parseBin(s), s };
#endif
        } else {
            return (Result) { errorObject(UNSUPPORTED_NUMBER_TYPE), s};
        }
    } else if (s->length == 1 && (c == 'T' || c == 't')) {
        return (Result) { boolObject(1), s};
    } else if (s->length == 1 && (c == 'F' || c == 'f')) {
        return (Result) { boolObject(0), s};
    } else if (c == '"'/* || c == '\''*/) {
        return (Result) { objFromSlice(s->text, s->length), s};
    } else {
        if (s->text[s->length] == '\'' && s->text[s->length + 1] == 's') {
            Object possessiveFunc = newObject(TYPE_FUNC);
            possessiveFunc.func = &possessive;
            Object list = startList(possessiveFunc);
            Object possesser = symFromSlice(s->text, s->length);
            nf_addToList(&list, possesser);
            struct Slice* next = s + 3;
            Object possessed = objFromSlice(&next->text[-1], next->length + 1);
            nf_addToList(&list, possessed);
            return (Result) { list, next };
        }
        return (Result) { symFromSlice(s->text, s->length), s};
    }
}

Object parseEval(const char* input, struct Environment* env)
{
    struct Error err = noError();

    struct Slice* tokens = nf_tokenize(input, &err);
    if (err.context != NULL) {
        Object o = errorWithContext(err.code, err.context);
        free(err.context);
        return o;
    }
    if (!tokens->text) {
        return symFromSlice(" ", 1);
    }

#ifdef DEBUG
    struct Slice *debug = tokens;
    printd("start slice\n");
    if (debug) {
        while (debug->text) {
            char tok[100];
            copySlice(tok, debug);
            printd("slice: '%s'\n", tok);
            debug++;
        }
    }
#endif

    int i = 0;
    int parens = 0;
    Object obj = numberObject(0);
    struct Slice* tok = tokens;
    while (tok[i].text != NULL) {
        if (tok[i].text[0] == '(') {
            parens++;
        } else if (tok[i].text[0] == ')') {
            parens--;
        }

        if (parens == 0) {
            cleanObject(&obj);
            Object parsed = parse(tok).obj;
            if (parsed.type == TYPE_ERROR) {
                obj = parsed;    // TODO Check necessity
                break;
            }
            if (tok[i].text[0] == ')') {
                // Skip `tok` past end of list that just closed
                tok = &tok[i + 1];
                i = -1;
            }
            if (parsed.type == TYPE_SLIST) {
                obj = parsed;
            } else {
                obj = eval(&parsed, env);
                cleanObject(&parsed);
            }
        }

        i++;
    }
    free(tokens);
    return obj;
}

#ifdef STANDALONE

int _readFile(FILE* input, struct Environment* env)
{
    Object r = numberObject(0);
    char page[4096] = "";
    const int LINE_MAX = 256;
    char line[LINE_MAX];
    if (fgets(line, LINE_MAX, input)) {
        if (line[0] != '#' || line[1] != '!') {
            strncat(page, line, strlen(line) - 1);
        }
    }
    int isQuote = 0;
    while (fgets(line, LINE_MAX, input)) {
        int i;
        for (i = 0; i < LINE_MAX; i++) {
            if (line[i] != ' ') {
                if (line[i] == ';') {
                    break;
                } else {
                    int j = 0;
                    for (j = i; j < LINE_MAX; j++) {
                        if (line[j] == '"') {
                            isQuote = !isQuote;
                        } else if (line[j] == '\0' || (!isQuote && line[j] == ';')) {
                            break;
                        }
                    }
                    strncat(page, line, j);
                    strcat(page, " ");
                    break;
                }
            }
        }
    }

    r = parseEval(page, env);
    cleanObject(&r);

    fclose(input);
    return 0;
}

int readFile(const char* filename, struct Environment* env)
{
    FILE* input = fopen(filename, "r");
    if (!input) {
        return 1;
    }
    _readFile(input, env);
    return 0;
}

Object loadFile(Object filename, Object _, struct Environment* env)
{
    if (isStringy(filename)) {
        readFile(filename.string, env);
        return numberObject(0);
    }
    return numberObject(1);
}

Object systemCall(Object process, Object _, struct Environment* env)
{
    if (isStringy(process)) {
        return numberObject(system(process.string));
    }
    return numberObject(255);
}

void repl(struct Environment* env)
{
    char* buf;
    while ((buf = readline("pebblisp::> ")) != NULL) {
        if (strcmp("q", buf) == 0) {
            free(buf);
            break;
        }
        Object o = parseEval(buf, env);
        printObj(&o);
        free(buf);
    }
}

void loadArgsIntoEnv(int argc, const char* argv[], struct Environment* env)
{
    Object args = listObject();
    for (int i = 0; i < argc; i++) {
        nf_addToList(&args, stringFromSlice(argv[i], strlen(argv[i])));
    }
    addToEnv(env, "args", args);
}

int main(int argc, const char* argv[])
{
    struct Environment env = defaultEnv();
    setGlobal(&env);
    readFile(SCRIPTDIR "/lib.pbl", &env);
    if (argc >= 2) {
        FILE* file = fopen(argv[1], "r");
        if (file) {
            // Executing a file
            loadArgsIntoEnv(argc, argv, &env);
            _readFile(file, &env);
        } else {
            // Running arguments directly as pl code
            Object r = numberObject(0);
            for (int i = 1; i < argc; i++) {
                r = parseEval(argv[i], &env);
                printAndClean(&r);
            }
        }
    } else {
        // Running a repl
        loadArgsIntoEnv(argc, argv, &env);
        repl(&env);
    }
    deleteEnv(&env);
}

#endif