exopen.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
/*
 * Glenn Fowler
 * AT&T Research
 *
 * expression library
 */
 
#include <expr/exlib.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
 
static void free_exid(void *p) {
  Exid_t *const exid = p;
 
  // the `Exid_t` itself was allocated through the program’s `vm` allocator, so
  // will be automatically deallocated, but we need to manually clean up the
  // `local` set that is used for arrays
  dtclose(exid->local);
}
 
/*
 * allocate a new expression program environment
 */
 
Expr_t*
exopen(Exdisc_t* disc)
{
        Expr_t* program;
        Exid_t* sym;
 
        if (!(program = calloc(1, sizeof(Expr_t))))
                return 0;
        static Dtdisc_t symdisc = {.key = offsetof(Exid_t, name), .freef = free_exid};
        if (!(program->symbols = dtopen(&symdisc, Dtset))) {
                exclose(program);
                return 0;
        }
        program->id = "libexpr:expr";
        program->disc = disc;
        setcontext(program);
        program->file[0] = stdin;
        program->file[1] = stdout;
        program->file[2] = stderr;
        program->main = (Exid_t){.lex = PROCEDURE, .index = PROCEDURE, .name = "main"};
        dtinsert(program->symbols, &program->main);
        for (sym = exbuiltin; *sym->name; sym++)
                dtinsert(program->symbols, sym);
        if ((sym = disc->symbols))
                for (; *sym->name; sym++)
                        dtinsert(program->symbols, sym);
        return program;
}