iris

small scheme interpreter
git clone git://git.2f30.org/iris.git
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commit 00d7556a1443ee2047887f20440320c459f1d272
parent 76e8179b214bea8c00515956c1602522caa759b6
Author: sin <sin@2f30.org>
Date:   Fri May 16 15:23:41 +0100

Add car, cdr and cons

Diffstat:
parser.c | 59+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+), 0 deletions(-)
diff --git a/parser.c b/parser.c @@ -74,6 +74,9 @@ static struct object *evalset(struct object *); /* primitive procedures */ static struct object *evalboolean(struct object *); +static struct object *evalcar(struct object *); +static struct object *evalcdr(struct object *); +static struct object *evalcons(struct object *); static struct object *evaldiff(struct object *); static struct object *evaleq(struct object *); static struct object *evalgt(struct object *); @@ -100,6 +103,9 @@ struct { struct object *(*fn)(struct object *); } procs[] = { { .name = "boolean", .fn = evalboolean }, + { .name = "car", .fn = evalcar }, + { .name = "cdr", .fn = evalcdr }, + { .name = "cons", .fn = evalcons }, { .name = "diff", .fn = evaldiff }, { .name = "eq", .fn = evaleq }, { .name = "gt", .fn = evalgt }, @@ -440,6 +446,59 @@ evalboolean(struct object *o) } static struct object * +evalcar(struct object *o) +{ + struct object *arg; + + if (o->type != OPair) + return NULL; + if (car(o)->type != OIdentifier || + strcmp(car(o)->d.i.name, "car") != 0) + return NULL; + if (caddr(o)) + return error("multiple arguments"); + arg = eval(cadr(o)); + if (arg->type == OError) + return arg; + if (arg->type != OPair) + return error("expected pair"); + return car(arg); +} + +static struct object * +evalcdr(struct object *o) +{ + struct object *arg; + + if (o->type != OPair) + return NULL; + if (car(o)->type != OIdentifier || + strcmp(car(o)->d.i.name, "cdr") != 0) + return NULL; + if (caddr(o)) + return error("multiple arguments"); + arg = eval(cadr(o)); + if (arg->type == OError) + return arg; + if (arg->type != OPair) + return error("expected pair"); + return cdr(arg); +} + +static struct object * +evalcons(struct object *o) +{ + if (o->type != OPair) + return NULL; + if (car(o)->type != OIdentifier || + strcmp(car(o)->d.i.name, "cons") != 0) + return NULL; + if (cadddr(o)) + return error("multiple arguments"); + return cons(eval(cadr(o)), eval(caddr(o))); +} + +static struct object * dodiff(struct object *o, struct object *n) { struct object *arg;