-/*
- Pass string to scm parser, evaluate one expression.
- Return result value and #chars read.
-
- Thanks to Gary Houston <ghouston@freewire.co.uk>
-
- Need guile-1.3.4 (>1.3 anyway) for ftell on str ports -- jcn
-*/
-SCM
-ly_parse_scm (char const* s, int* n)
-{
- SCM str = ly_str02scm (s);
- SCM port = scm_mkstrport (SCM_INUM0, str, SCM_OPN | SCM_RDNG,
- "ly_eval_scm_0str");
- SCM from = scm_ftell (port);
-
- SCM form;
- SCM answer = SCM_UNSPECIFIED;
-
- /* Read expression from port */
- if (!SCM_EOF_OBJECT_P (form = scm_read (port)))
- answer = scm_primitive_eval (form);
-
- /*
- After parsing
-
- (begin (foo 1 2))
-
- all seems fine, but after parsing
-
- (foo 1 2)
-
- read_buf has been advanced to read_pos - 1,
- so that scm_ftell returns 1, instead of #parsed chars
- */
-
- /*
- urg: reset read_buf for scm_ftell
- shouldn't scm_read () do this for us?
- */
- scm_fill_input (port);
- SCM to = scm_ftell (port);
- *n = gh_scm2int (to) - gh_scm2int (from);
-
- /* Don't close the port here; if we re-enter this function via a
- continuation, then the next time we enter it, we'll get an error.
- It's a string port anyway, so there's no advantage to closing it
- early.
-
- scm_close_port (port);
- */
-
- return answer;
-}
-