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#include "./include/visitor.h"
#include "./include/hash_table.h"
#include "./include/macros.h"
#include "./include/parser.h"
#include "./include/stack.h"
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
visitor_t *init_visitor(parser_t *p) {
visitor_t *v = (visitor_t *)malloc(sizeof(visitor_t));
if (v == NULL)
die("malloc on visitor");
v->stack_frame = init_stack(512);
v->symbol_table = p->symbol_table;
v->eval_table = init_hash_table(1000);
v->root = parse_all(p);
return v;
}
bool is_self_evaluating(ast_t *e) {
if (e->type == AST_STRING || e->type == AST_INT || e->type == AST_FLOAT ||
e->type == AST_BOOL || e->type == AST_FUNCTION)
return true;
if (e->type == AST_PAIR && e->car == NULL && e->cdr == NULL)
return true;
return false;
}
bool is_built_in(ast_t *e) {
char *cmp = e->string_value;
/* Basic mathematics */
if (strcmp(cmp, "*") == 0 || strcmp(cmp, "+") == 0 || strcmp(cmp, "-") == 0 ||
strcmp(cmp, "/") == 0 || strcmp(cmp, "%") == 0)
return true;
/* Some string and list operations */
if (strcmp(cmp, "concat") == 0 || strcmp(cmp, "len") == 0 ||
strcmp(cmp, "car") == 0 || strcmp(cmp, "cdr") == 0 ||
strcmp(cmp, "cons") == 0 || strcmp(cmp, "quote") == 0)
return true;
/* Comparison functions */
if (strcmp(cmp, "<") == 0 || strcmp(cmp, ">") == 0 || strcmp(cmp, "=") == 0 ||
strcmp(cmp, "<=") == 0 || strcmp(cmp, ">=") == 0 ||
strcmp(cmp, "eq") == 0)
return true;
/* Type-checking */
if (strcmp(cmp, "bool?") == 0 || strcmp(cmp, "int?") == 0 ||
strcmp(cmp, "symbol?") == 0 || strcmp(cmp, "float?") == 0 ||
strcmp(cmp, "string?") == 0 || strcmp(cmp, "pair?") == 0 ||
strcmp(cmp, "func?") == 0)
return true;
/* Type conversions */
if (strcmp(cmp, "atoi") == 0 || strcmp(cmp, "itof") == 0 ||
strcmp(cmp, "ftoi") == 0 || strcmp(cmp, "itoa") == 0 ||
strcmp(cmp, "atof") == 0 || strcmp(cmp, "ftoa") == 0)
return true;
return false;
}
/* Special symbols: car, cdr, quote, *, /, +, -, %, inc, dec, >, <, >=, <=, /=,
* =, equal (for strings), input */
ast_t *eval_symbol(visitor_t *v, ast_t *e) {
if (is_built_in(e))
return e;
/* first, it looks in the stack frame for a variable */
else if (hash_table_exists(stack_peek(v->stack_frame), e->string_value))
return hash_table_get(stack_peek(v->stack_frame), e->string_value);
/* Then the variables that have already been evaluated */
else if (hash_table_exists(v->eval_table, e->string_value))
return hash_table_get(v->eval_table, e->string_value);
/* then it goes into the symbol table, evaluates the variable if it finds it
* and puts it in the list of variables that have already been evaluated */
else if (hash_table_exists(v->symbol_table, e->string_value)) {
ast_t *unevaled = hash_table_get(v->symbol_table, e->string_value);
ast_t *eval = eval_expr(v, unevaled);
hash_table_add(v->eval_table, e->string_value, eval);
return eval;
} else
eval_error(v, e);
}
/* Helper function to get the size of an AST linked list; useful for checking
* parameter number */
int get_list_size(ast_t *root) {
if (root->type != AST_PAIR)
return -1;
int size = 0;
ast_t *cur = root;
while (cur->cdr != NULL) {
size++;
cur = cur->cdr;
}
return size;
}
ast_t *eval_list(visitor_t *v, ast_t *e) {
ast_t *function = eval_expr(v, e->car);
ast_t *args = e->cdr;
int arg_size;
int cmp = get_list_size(args);
/* BUILT-IN FUNCTIONS */
if (function->type == AST_SYMBOL) {
if (strcmp(function->string_value, "+") == 0) {
if (cmp != 2)
eval_error(v, e);
ast_t *arg1 = eval_expr(v, args->car);
ast_t *arg2 = eval_expr(v, args->cdr->car);
if ((arg1->type == AST_INT) && (arg2->type == AST_INT)) {
return init_ast_int(arg1->int_value + arg2->int_value);
} else if ((arg1->type == AST_INT) && (arg2->type == AST_FLOAT)) {
return init_ast_float(arg1->int_value + arg2->float_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type == AST_INT)) {
return init_ast_float(arg1->float_value + arg2->int_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type) == AST_FLOAT) {
return init_ast_float(arg1->float_value + arg2->float_value);
} else
eval_error(v, e);
} else if (strcmp(function->string_value, "-") == 0) {
if (cmp != 2)
eval_error(v, e);
ast_t *arg1 = eval_expr(v, args->car);
ast_t *arg2 = eval_expr(v, args->cdr->car);
if ((arg1->type == AST_INT) && (arg2->type == AST_INT)) {
return init_ast_int(arg1->int_value - arg2->int_value);
} else if ((arg1->type == AST_INT) && (arg2->type == AST_FLOAT)) {
return init_ast_float(arg1->int_value - arg2->float_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type == AST_INT)) {
return init_ast_float(arg1->float_value - arg2->int_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type) == AST_FLOAT) {
return init_ast_float(arg1->float_value - arg2->float_value);
} else
eval_error(v, e);
} else if (strcmp(function->string_value, "*") == 0) {
if (cmp != 2)
eval_error(v, e);
ast_t *arg1 = eval_expr(v, args->car);
ast_t *arg2 = eval_expr(v, args->cdr->car);
if ((arg1->type == AST_INT) && (arg2->type == AST_INT)) {
return init_ast_int(arg1->int_value * arg2->int_value);
} else if ((arg1->type == AST_INT) && (arg2->type == AST_FLOAT)) {
return init_ast_float(arg1->int_value * arg2->float_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type == AST_INT)) {
return init_ast_float(arg1->float_value * arg2->int_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type) == AST_FLOAT) {
return init_ast_float(arg1->float_value * arg2->float_value);
} else
eval_error(v, e);
} else if (strcmp(function->string_value, "/") == 0) {
if (cmp != 2)
eval_error(v, e);
ast_t *arg1 = eval_expr(v, args->car);
ast_t *arg2 = eval_expr(v, args->cdr->car);
if ((arg1->type == AST_INT) && (arg2->type == AST_INT)) {
return init_ast_float(arg1->int_value / arg2->int_value);
} else if ((arg1->type == AST_INT) && (arg2->type == AST_FLOAT)) {
return init_ast_float(arg1->int_value / arg2->float_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type == AST_INT)) {
return init_ast_float(arg1->float_value / arg2->int_value);
} else if ((arg1->type == AST_FLOAT) && (arg2->type) == AST_FLOAT) {
return init_ast_float(arg1->float_value / arg2->float_value);
} else
eval_error(v, e);
} else if (strcmp(function->string_value, "%") == 0) {
if (cmp != 2)
eval_error(v, e);
ast_t *arg1 = eval_expr(v, args->car);
ast_t *arg2 = eval_expr(v, args->cdr->car);
if ((arg1->type == AST_INT) && (arg2->type == AST_INT)) {
return init_ast_int(arg1->int_value * arg2->int_value);
} else
eval_error(v, e);
}
}
/* NON BUILT-INS */
/* Checking that the parameters are actually valid */
if (function->type != AST_FUNCTION)
eval_error(v, e->car);
arg_size = get_list_size(function->car);
if (arg_size != cmp)
eval_error(v, e->car);
hash_table_t *stack_frame = init_hash_table(512);
ast_t *cur_arg_name = function->car;
ast_t *cur_arg = args;
char *name;
ast_t *evaled_arg;
while (cur_arg != NULL && cur_arg_name != NULL) {
name = cur_arg_name->car->string_value;
evaled_arg = eval_expr(v, cur_arg->car);
hash_table_add(stack_frame, name, evaled_arg);
cur_arg_name = cur_arg_name->cdr;
cur_arg = cur_arg->cdr;
}
stack_push(v->stack_frame, stack_frame);
ast_t *res = eval_expr(v, function->cdr);
stack_frame = stack_pop(v->stack_frame);
hash_table_free(stack_frame);
return res;
}
ast_t *eval_expr(visitor_t *v, ast_t *e) {
if (is_self_evaluating(e))
return e;
else if (e->type == AST_PAIR)
return eval_list(v, e);
else if (e->type == AST_SYMBOL)
return eval_symbol(v, e);
else {
eval_error(v, e);
}
}
ast_t *eval(visitor_t *v) {
ast_t *cur;
ast_t *root;
ast_t **eval_nodes = malloc(sizeof(ast_t *));
for (int i = 0; i < v->root->root_size; i++) {
cur = eval_expr(v, v->root->subnodes[i]);
eval_nodes = realloc(eval_nodes, (i + 1) * sizeof(ast_t *));
eval_nodes[i] = cur;
}
root = init_ast_root(eval_nodes, v->root->root_size);
return root;
}
void eval_error(visitor_t *v, ast_t *e) {
printf("ERROR: something went wrong with the visitor.\n");
exit(1);
}
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