#include <math.h>
#include <string.h>
+#include "./builtins.h"
+#include "./expr.h"
#include "./interpreter.h"
+#include "./scope.h"
-#define FLOAT_EQUALS_MARGIN 1e-6
+struct EvalResult eval_success(struct Expr expr, struct Expr scope)
+{
+ struct EvalResult result = {
+ .is_error = false,
+ .expr = expr,
+ .scope = scope,
+ };
+
+ return result;
+}
-static bool equal_atoms(struct Atom *atom1, struct Atom *atom2)
+struct EvalResult eval_failure(struct Expr error, struct Expr scope)
{
- assert(atom1);
- assert(atom2);
+ struct EvalResult result = {
+ .is_error = true,
+ .expr = error,
+ .scope = scope
+ };
- if (atom1->type != atom2->type) {
- return false;
- }
+ return result;
+}
- switch (atom1->type) {
- case ATOM_SYMBOL:
- return strcmp(atom1->sym, atom2->sym) == 0;
+static struct EvalResult length(Gc *gc, struct Expr scope, struct Expr obj)
+{
+ if (!list_p(obj)) {
+ return eval_failure(list(gc, 3,
+ SYMBOL(gc, "wrong-argument-type"),
+ SYMBOL(gc, "listp"),
+ obj),
+ scope);
+ }
- case ATOM_NUMBER:
- return fabsf(atom1->num - atom2->num) <= FLOAT_EQUALS_MARGIN;
+ long int count = 0;
- case ATOM_STRING:
- return strcmp(atom1->str, atom2->str) == 0;
+ while (!nil_p(obj)) {
+ count++;
+ obj = obj.cons->cdr;
}
- return false;
+ return eval_success(NUMBER(gc, count), scope);
}
-static bool equal_cons(struct Cons *cons1, struct Cons *cons2)
+static struct EvalResult eval_atom(Gc *gc, struct Expr scope, struct Atom *atom)
{
- assert(cons1);
- assert(cons2);
- return equal(cons1->car, cons2->car) && equal(cons1->cdr, cons2->cdr);
+ (void) scope;
+ (void) gc;
+
+ /* TODO(#314): Evaluating symbols is not implemented */
+ switch (atom->type) {
+ case ATOM_NUMBER:
+ case ATOM_SYMBOL:
+ case ATOM_STRING:
+ return eval_success(atom_as_expr(atom), scope);
+ }
+
+ return eval_failure(CONS(gc,
+ SYMBOL(gc, "unexpected-expression"),
+ atom_as_expr(atom)),
+ scope);
}
-bool equal(struct Expr obj1, struct Expr obj2)
+static struct EvalResult eval_all_args(Gc *gc, struct Expr scope, struct Expr args)
{
- if (obj1.type != obj2.type) {
- return false;
- }
+ (void) scope;
+ (void) args;
- switch (obj1.type) {
+ switch(args.type) {
case EXPR_ATOM:
- return equal_atoms(obj1.atom, obj2.atom);
+ return eval_atom(gc, scope, args.atom);
- case EXPR_CONS:
- return equal_cons(obj1.cons, obj2.cons);
+ case EXPR_CONS: {
+ struct EvalResult car = eval(gc, scope, args.cons->car);
+ if (car.is_error) {
+ return car;
+ }
- case EXPR_VOID:
- return true;
+ struct EvalResult cdr = eval_all_args(gc, scope, args.cons->cdr);
+ if (cdr.is_error) {
+ return cdr;
+ }
+
+ return eval_success(cons_as_expr(create_cons(gc, car.expr, cdr.expr)), scope);
+ }
+
+ default: {}
}
- return false;
+ return eval_failure(CONS(gc,
+ SYMBOL(gc, "unexpected-expression"),
+ args),
+ scope);
}
-struct Expr assoc(struct Expr key)
+static struct EvalResult plus_op(Gc *gc, struct Expr args, struct Expr scope)
{
- /* TODO: assoc is not implemented */
- return key;
+ long int result = 0.0f;
+
+ while (!nil_p(args)) {
+ if (args.type != EXPR_CONS) {
+ return eval_failure(CONS(gc,
+ SYMBOL(gc, "expected-cons"),
+ args),
+ scope);
+ }
+
+ if (args.cons->car.type != EXPR_ATOM ||
+ args.cons->car.atom->type != ATOM_NUMBER) {
+ return eval_failure(CONS(gc,
+ SYMBOL(gc, "expected-number"),
+ args.cons->car),
+ scope);
+ }
+
+ result += args.cons->car.atom->num;
+ args = args.cons->cdr;
+ }
+
+ return eval_success(atom_as_expr(create_number_atom(gc, result)), scope);
+}
+
+static struct EvalResult eval_funcall(Gc *gc, struct Expr scope, struct Cons *cons)
+{
+ assert(cons);
+ (void) scope;
+
+ if (!symbol_p(cons->car)) {
+ return eval_failure(CONS(gc,
+ SYMBOL(gc, "expected-symbol"),
+ cons->car),
+ scope);
+ }
+
+ /* TODO(#323): set builtin function is not implemented */
+ if (strcmp(cons->car.atom->sym, "+") == 0) {
+ struct EvalResult args = eval_all_args(gc, scope, cons->cdr);
+ if (args.is_error) {
+ return args;
+ }
+ return plus_op(gc, args.expr, scope);
+ } else if (strcmp(cons->car.atom->sym, "set") == 0) {
+ struct Expr args = cons->cdr;
+ struct EvalResult n = length(gc, scope, args);
+
+ if (n.is_error) {
+ return n;
+ }
+ scope = n.scope;
+
+ if (n.expr.atom->num != 2) {
+ return eval_failure(list(gc, 3,
+ SYMBOL(gc, "wrong-number-of-arguments"),
+ SYMBOL(gc, "set"),
+ NUMBER(gc, n.expr.atom->num)),
+ scope);
+ }
+
+ struct Expr name = args.cons->car;
+ if (!symbol_p(name)) {
+ return eval_failure(list(gc, 3,
+ SYMBOL(gc, "wrong-type-argument"),
+ SYMBOL(gc, "symbolp"),
+ name),
+ scope);
+ }
+
+ struct EvalResult value = eval(gc, scope, args.cons->cdr.cons->car);
+ if (value.is_error) {
+ return value;
+ }
+ scope = value.scope;
+
+ return eval_success(value.expr, set_scope_value(gc, scope, name, value.expr));
+ }
+
+ return eval_failure(CONS(gc,
+ SYMBOL(gc, "unknown-function"),
+ cons->car),
+ scope);
}
-struct Expr eval(struct Expr expr)
+struct EvalResult eval(Gc *gc, struct Expr scope, struct Expr expr)
{
- /* TODO: eval is not implemented */
- return expr;
+ switch(expr.type) {
+ case EXPR_ATOM:
+ return eval_atom(gc, scope, expr.atom);
+
+ case EXPR_CONS:
+ return eval_funcall(gc, scope, expr.cons);
+
+ default: {}
+ }
+
+ return eval_failure(CONS(gc,
+ SYMBOL(gc, "unexpected-expression"),
+ expr),
+ scope);
}
projects / nothing.git / blobdiff