mes/src/reader.c

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/* -*-comment-start: "//";comment-end:""-*-
* Mes --- Maxwell Equations of Software
* Copyright © 2016,2017 Jan Nieuwenhuizen <janneke@gnu.org>
*
* This file is part of Mes.
*
* Mes is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* Mes is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Mes. If not, see <http://www.gnu.org/licenses/>.
*/
// #if _POSIX_SOURCE
// #undef fputs
// #undef fdputs
// #undef fdputc
// #endif
SCM
___end_of_mes___ ()
{
return 0;
}
SCM
read_input_file_env_ (SCM e, SCM a)
{
if (e == cell_nil) return e;
return cons (e, read_input_file_env_ (read_env (a), a));
}
SCM
read_input_file_env (SCM a)
{
r0 = a;
if (assq_ref_env (cell_symbol_read_input_file, r0) != cell_undefined)
return apply (cell_symbol_read_input_file, cell_nil, r0);
return read_input_file_env_ (read_env (r0), r0);
}
int
read_line_comment (int c)
{
if (c == '\n') return c;
return read_line_comment (getchar ());
}
SCM
read_word (int c, SCM w, SCM a)
{
if (c == EOF && w == cell_nil) return cell_nil;
if (c == '\t') return read_word ('\n', w, a);
if (c == '\f') return read_word ('\n', w, a);
if (c == '\n' && w == cell_nil) return read_word (getchar (), w, a);
if (c == '\n' && VALUE (car (w)) == '.' && cdr (w) == cell_nil) return cell_dot;
if (c == EOF || c == '\n') return lookup_ (w, a);
if (c == ' ') return read_word ('\n', w, a);
if (c == '(' && w == cell_nil) return read_list (a);
if (c == '(') {ungetchar (c); return lookup_ (w, a);}
if (c == ')' && w == cell_nil) {ungetchar (c); return cell_nil;}
if (c == ')') {ungetchar (c); return lookup_ (w, a);}
if (c == ';') {read_line_comment (c); return read_word ('\n', w, a);}
return read_word (getchar (), append2 (w, cons (MAKE_CHAR (c), cell_nil)), a);
}
int
eat_whitespace (int c)
{
while (c == ' ' || c == '\t' || c == '\n' || c == '\f') c = getchar ();
if (c == ';') return eat_whitespace (read_line_comment (c));
return c;
}
SCM
read_list (SCM a)
{
int c = getchar ();
c = eat_whitespace (c);
if (c == ')') return cell_nil;
SCM w = read_word (c, cell_nil, a);
if (w == cell_dot)
return car (read_list (a));
return cons (w, read_list (a));
}
SCM
read_env (SCM a)
{
return read_word (getchar (), cell_nil, a);
}
SCM
lookup_ (SCM s, SCM a)
{
if (isdigit (VALUE (car (s))) || (VALUE (car (s)) == '-' && cdr (s) != cell_nil)) {
SCM p = s;
int sign = 1;
if (VALUE (car (s)) == '-') {
sign = -1;
p = cdr (s);
}
int n = 0;
while (p != cell_nil && isdigit (VALUE (car (p)))) {
n *= 10;
n += VALUE (car (p)) - '0';
p = cdr (p);
}
if (p == cell_nil) return MAKE_NUMBER (n * sign);
}
return lookup_symbol_ (s);
}
int g_tiny = 0;
int
dump ()
{
r1 = g_symbols;
gc_push_frame ();
gc ();
gc_peek_frame ();
char *p = (char*)g_cells;
putchar ('M');
putchar ('E');
putchar ('S');
putchar (g_stack >> 8);
putchar (g_stack % 256);
// See HACKING, simple crafted dump for tiny-mes.c
if (g_tiny || getenv ("MES_TINY"))
{
eputs ("dumping TINY\n");
TYPE (9) = 0x2d2d2d2d;
CAR (9) = 0x2d2d2d2d;
CDR (9) = 0x3e3e3e3e;
TYPE (10) = TPAIR;
CAR (10) = 11;
CDR (10) = 12;
TYPE (11) = TCHAR;
CAR (11) = 0x58585858;
CDR (11) = 65;
TYPE (12) = TPAIR;
CAR (12) = 13;
CDR (12) = 1;
TYPE (13) = TCHAR;
CAR (11) = 0x58585858;
CDR (13) = 66;
TYPE (14) = 0x3c3c3c3c;
CAR (14) = 0x2d2d2d2d;
CDR (14) = 0x2d2d2d2d;
g_free = 15;
}
else
{
eputs ("dumping FULL\n");
if (g_debug > 1)
{
eputs ("program r2=");
display_error_ (r2);
eputs ("\n");
}
}
for (int i=0; i<g_free * sizeof(struct scm); i++)
putchar (*p++);
return 0;
}