~snowball-yiddish-dev/snowball-yiddish/trunk : contents of snowball/compiler/generator.c at revision 246

~snowball-yiddish-dev/snowball-yiddish/trunk : (revision 246)
#include <stdio.h>   /* for fprintf etc */
#include <stdlib.h>  /* for free etc */
#include <string.h>  /* for strlen */
#include "header.h"

/* recursive use: */

static void generate(struct generator * g, struct node * p);

enum special_labels {

    x_return = -1

};

static int new_label(struct generator * g)
{   return g->next_label++;
}

/* Output routines */
static void output_str(FILE * outfile, struct str * str)
{
    char * s = b_to_s(str_data(str));
    fprintf(outfile, "%s", s);
    free(s);
}

static void wch(struct generator * g, int ch)
{   str_append_ch(g->outbuf, ch); /* character */
}

static void wnl(struct generator * g)
{   str_append_ch(g->outbuf, '\n'); /* newline */
    g->line_count++;
}

static void ws(struct generator * g, char * s)
{   str_append_string(g->outbuf, s); /* string */
}

static void wi(struct generator * g, int i)
{   str_append_int(g->outbuf, i); /* integer */
}

static void wi3(struct generator * g, int i)
{   if (i < 100) wch(g, ' ');
    if (i < 10)  wch(g, ' ');
    wi(g, i); /* integer (width 3) */
}

static void wvn(struct generator * g, struct name * p)  /* variable name */
{
    int ch = "SBIrxg"[p->type];
    switch (p->type)
    {   case t_string:
        case t_boolean:
        case t_integer:
            wch(g, ch); wch(g, '['); wi(g, p->count); wch(g, ']'); return;
        case t_external:
            ws(g, g->options->externals_prefix); break;
        default:
            wch(g, ch); wch(g, '_');
    }
    str_append_b(g->outbuf, p->b);
}

static void wv(struct generator * g, struct name * p)  /* reference to variable */
{   if (p->type < t_routine) ws(g, "z->");
    wvn(g, p);
}

static void wlitarray(struct generator * g, symbol * p)  /* write literal array */
{
    ws(g, "{ ");
    {   int i;
        for (i = 0; i < SIZE(p); i++)
        {   int ch = p[i];
            if (32 <= ch && ch <= 127)
            {   wch(g, '\'');
                switch (ch)
                {   case '\'':
                    case '\\': wch(g, '\\');
                    default:   wch(g, ch);
                }
                wch(g, '\'');
            }  else wi(g, ch);
            if (i < SIZE(p) - 1) ws(g, ", ");
        }
    }
    ws(g, " }");
}

static void wlitref(struct generator * g, symbol * p)  /* write ref to literal array */
{
    if (SIZE(p) == 0) ws(g, "0"); else
    {
        struct str * s = g->outbuf;
        g->outbuf = g->declarations;
        ws(g, "static symbol s_"); wi(g, g->literalstring_count); ws(g, "[] = ");
        wlitarray(g, p);
        ws(g, ";\n");
        g->outbuf = s;
        ws(g, "s_"); wi(g, g->literalstring_count);
        g->literalstring_count++;
    }
}


static void wm(struct generator * g)       /* margin */
{   int i;
    for (i = 0; i < g->margin; i++) ws(g, "    ");
}

static void wc(struct generator * g, struct node * p) /* comment */
{
    ws(g, " /* ");
    ws(g, (char *) name_of_token(p->type));
    unless (p->name == 0)
    {   ws(g, " ");
        str_append_b(g->outbuf, p->name->b);
    }
    ws(g, ", line "); wi(g, p->line_number); ws(g, " */");
    wnl(g);
}

static void wms(struct generator * g, char * s)
{   wm(g); ws(g, s);   } /* margin + string */

static void wbs(struct generator * g) /* block start */
{   wms(g, "{   ");
    g->margin++;
}

static void wbe(struct generator * g)    /* block end */
{
    if (g->line_labelled == g->line_count) { wms(g, ";"); wnl(g); }
    g->margin--;
    wms(g, "}"); wnl(g);
}

static void wk(struct generator * g, struct node * p)     /* keep c */
{   ws(g, p->mode == m_forward ? "int c = z->c;" :
                                 "int m = z->l - z->c;");
}

static char * restore_string(struct generator * g, struct node * p)
{
    (void) g;
    return p->mode == m_forward ? "z->c = c;" :
                                  "z->c = z->l - m;";
}

static void wr(struct generator * g, struct node * p)     /* restore c */
{   ws(g, restore_string(g, p));
}

static void winc(struct generator * g, struct node * p)     /* increment c */
{   ws(g, p->mode == m_forward ? "z->c++;" :
                                 "z->c--;");
}

static void wsetl(struct generator * g, int n)
{   g->margin--;
    wms(g, "lab"); wi(g, n); wch(g, ':'); wnl(g);
    g->line_labelled = g->line_count;
    g->margin++;
}

static void wgotol(struct generator * g, int n)
{   wms(g, "goto lab"); wi(g, n); wch(g, ';'); wnl(g);
}

static void wf(struct generator * g)          /* fail */
{   if (g->failure_string != 0) { ws(g, "{ "); ws(g, g->failure_string); wch(g, ' '); }
    switch (g->failure_label)
    {
        case x_return:
           ws(g, "return 0;"); break;
        default:
           ws(g, "goto lab"); wi(g, g->failure_label); wch(g, ';');
    }
    if (g->failure_string != 0) ws(g, " }");
}

static void wlim(struct generator * g, struct node * p)     /* if at limit fail */
{
    ws(g, p->mode == m_forward ? "if (z->c >= z->l) " :
                                 "if (z->c <= z->lb) ");
    wf(g);
}

static void wp(struct generator * g, char * s, struct node * p) /* formatted write */
{   int i = 0;
    int l = strlen(s);
    until (i >= l)
    {   int ch = s[i++];
        if (ch != '~') wch(g, ch); else
        switch(s[i++])
        {   default:  wch(g, s[i - 1]); continue;
            case 'C': wc(g, p); continue;
            case 'k': wk(g, p); continue;
            case 'K': /* keep for c_test */
                ws(g, p->mode == m_forward ? "int c_test = z->c;" :
                                             "int m_test = z->l - z->c;");
                continue;
            case 'r': wr(g, p); continue;
            case 'R': /* restore for c_test */
                ws(g, p->mode == m_forward ? "z->c = c_test;" :
                                             "z->c = z->l - m_test;");
                continue;
            case 'i': winc(g, p); continue;
            case 'l': wlim(g, p); continue;
            case 'f': wf(g); continue;
            case 'M': wm(g); continue;
            case 'N': wnl(g); continue;
            case '{': wbs(g); continue;
            case '}': wbe(g); continue;
            case 'S': ws(g, g->S[s[i++] - '0']); continue;
            case 'I': wi(g, g->I[s[i++] - '0']); continue;
            case 'J': wi3(g, g->I[s[i++] - '0']); continue;
            case 'V': wv(g, g->V[s[i++] - '0']); continue;
            case 'W': wvn(g, g->V[s[i++] - '0']); continue;
            case 'L': wlitref(g, g->L[s[i++] - '0']); continue;
            case 'A': wlitarray(g, g->L[s[i++] - '0']); continue;
            case '+': g->margin++; continue;
            case '-': g->margin--; continue;
            case '$': /* insert_s, insert_v etc */
                wch(g, p->literalstring == 0 ? 'v' : 's');
                continue;
            case 'p': ws(g, g->options->externals_prefix); continue;
        }
    }
}

static void w(struct generator * g, char * s) { wp(g, s, 0); }

static void generate_AE(struct generator * g, struct node * p)
{   char * s;
    switch (p->type)
    {   case c_name:
            wv(g, p->name); break;
        case c_number:
            wi(g, p->number); break;
        case c_maxint:
            ws(g, "MAXINT"); break;
        case c_minint:
            ws(g, "MININT"); break;
        case c_neg:
            wch(g, '-'); generate_AE(g, p->right); break;
        case c_multiply:
            s = " * "; goto label0;
        case c_plus:
            s = " + "; goto label0;
        case c_minus:
            s = " - "; goto label0;
        case c_divide:
            s = " / ";
        label0:
            wch(g, '('); generate_AE(g, p->left);
            ws(g, s); generate_AE(g, p->right); wch(g, ')'); break;
        case c_sizeof:
            g->V[0] = p->name;
            w(g, "SIZE(~V0)"); break;
        case c_cursor:
            w(g, "z->c"); break;
        case c_limit:
            w(g, p->mode == m_forward ? "z->l" : "z->lb"); break;
        case c_size:
            w(g, "SIZE(z->p)"); break;
    }
}

/* K_needed() tests to see if we really need to keep c. Not true when the
   the command does not touch the cursor. This and repeat_score() could be
   elaborated almost indefinitely.
*/

static int K_needed(struct generator * g, struct node * p)
{   until (p == 0)
    {   switch (p->type)
        {   case c_dollar:
            case c_leftslice:
            case c_rightslice:
            case c_mathassign:
            case c_plusassign:
            case c_minusassign:
            case c_multiplyassign:
            case c_divideassign:
            case c_eq:
            case c_ne:
            case c_gr:
            case c_ge:
            case c_ls:
            case c_le:
            case c_sliceto:
            case c_true:
            case c_false:
            case c_debug:
                break;

            case c_call:
                if (K_needed(g, p->name->definition)) return true;
                break;

            case c_bra:
                if (K_needed(g, p->left)) return true;
                break;

            default: return true;
        }
        p = p->right;
    }
    return false;
}

static int repeat_score(struct generator * g, struct node * p)
{   int score = 0;
    until (p == 0)
    {
        switch (p->type)
        {   case c_dollar:
            case c_leftslice:
            case c_rightslice:
            case c_mathassign:
            case c_plusassign:
            case c_minusassign:
            case c_multiplyassign:
            case c_divideassign:
            case c_eq:
            case c_ne:
            case c_gr:
            case c_ge:
            case c_ls:
            case c_le:
            case c_sliceto:   /* case c_not: must not be included here! */
            case c_debug:
                break;

            case c_call:
                score += repeat_score(g, p->name->definition);
                break;

            case c_bra:
                score += repeat_score(g, p->left);
                break;

            case c_name:
            case c_literalstring:
            case c_next:
            case c_grouping:
            case c_non:
            case c_hop:
                score = score + 1; break;

            default: score = 2; break;
        }
        p = p->right;
    }
    return score;
}

/* tests if an expression requires cursor reinstatement in a repeat */

static int repeat_restore(struct generator * g, struct node * p)
{   return repeat_score(g, p) >= 2;
}

static void generate_bra(struct generator * g, struct node * p)
{   p = p->left;
    until (p == 0) { generate(g, p); p = p->right; }
}

static void generate_and(struct generator * g, struct node * p)
{   int keep_c = K_needed(g, p->left);
    if (keep_c) wp(g, "~{~k~C", p);
           else wp(g, "~M~C", p);
    p = p->left;
    until (p == 0)
    {   generate(g, p);
        if (keep_c && p->right != 0) wp(g, "~M~r~N", p);
        p = p->right;
    }
    if (keep_c) w(g, "~}");
}

static void generate_or(struct generator * g, struct node * p)
{   int keep_c = K_needed(g, p->left);

    int a0 = g->failure_label;
    char * a1 = g->failure_string;

    int out_lab = new_label(g);

    if (keep_c) wp(g, "~{~k~C", p);
           else wp(g, "~M~C", p);
    p = p->left;
    g->failure_string = 0;
    until (p == 0)
    {   if (p->right != 0)
        {
            g->failure_label = new_label(g);
            generate(g, p);
            wgotol(g, out_lab);
            wsetl(g, g->failure_label);
            if (keep_c) wp(g, "~M~r~N", p);
        } else
        {
            g->failure_label = a0;
            g->failure_string = a1;

            generate(g, p);
            if (keep_c) w(g, "~}");
            wsetl(g, out_lab);
        }
        p = p->right;
    }
}

static void generate_backwards(struct generator * g, struct node * p)
{
    wp(g,"~Mz->lb = z->c; z->c = z->l;~C~N", p);
    generate(g, p->left);
    w(g, "~Mz->c = z->lb;~N");
}


static void generate_not(struct generator * g, struct node * p)
{   int keep_c = K_needed(g, p->left);

    int a0 = g->failure_label;
    char * a1 = g->failure_string;

    if (keep_c) wp(g, "~{~k~C", p);
           else wp(g, "~M~C", p);

    g->failure_label = new_label(g);
    g->failure_string = 0;
    generate(g, p->left);

    {   int l = g->failure_label;

        g->failure_label = a0;
        g->failure_string = a1;

        w(g, "~M~f~N");
        wsetl(g, l);
    }
    if (keep_c) wp(g, "~M~r~N"
                   "~}", p);
}


static void generate_try(struct generator * g, struct node * p)
{   int keep_c = K_needed(g, p->left);

    if (keep_c) wp(g, "~{~k~C", p);
           else wp(g, "~M~C", p);

    g->failure_label = new_label(g);
    g->failure_string = keep_c ? restore_string(g, p) : 0;
    generate(g, p->left);

    wsetl(g, g->failure_label);

    if (keep_c) w(g, "~}");
}

static void generate_set(struct generator * g, struct node * p)
{   g->V[0] = p->name; wp(g, "~M~V0 = 1;~C", p);
}

static void generate_unset(struct generator * g, struct node * p)
{   g->V[0] = p->name; wp(g, "~M~V0 = 0;~C", p);
}

static void generate_fail(struct generator * g, struct node * p)
{   generate(g, p->left);
    wp(g, "~M~f~C", p);
}

/* generate_test() also implements 'reverse' */

static void generate_test(struct generator * g, struct node * p)
{   int keep_c = K_needed(g, p->left);
    if (keep_c) wp(g, "~{~K~C", p);
           else wp(g, "~M~C", p);

    generate(g, p->left);

    if (keep_c) wp(g, "~M~R~N"
                   "~}", p);
}

static void generate_do(struct generator * g, struct node * p)
{   int keep_c = K_needed(g, p->left);
    if (keep_c) wp(g, "~{~k~C", p);
           else wp(g, "~M~C", p);

    g->failure_label = new_label(g);
    g->failure_string = 0;
    generate(g, p->left);

    wsetl(g, g->failure_label);
    if (keep_c) wp(g, "~M~r~N"
                   "~}", p);
}

static void generate_GO(struct generator * g, struct node * p, int style)
{   int keep_c = style == 1 || repeat_restore(g, p->left);

    int a0 = g->failure_label;
    char * a1 = g->failure_string;

    w(g, "~Mwhile(1) {"); wp(g, "~C~+", p);

    if (keep_c) wp(g, "~M~k~N", p);

    g->failure_label = new_label(g);
    generate(g, p->left);

    if (style == 1) wp(g, "~M~r~N", p);  /* include for goto; omit for gopast */
    w(g, "~Mbreak;~N");
    wsetl(g, g->failure_label);
    if (keep_c) wp(g, "~M~r~N", p);

    g->failure_label = a0;
    g->failure_string = a1;

    wp(g, "~M~l~N"
          "~M~i~N"
       "~}", p);
}

static void generate_loop(struct generator * g, struct node * p)
{   w(g, "~{int i; for (i = "); generate_AE(g, p->AE); wp(g, "; i > 0; i--)~C"
            "~{", p);

    generate(g, p->left);

    w(g,    "~}"
         "~}");
}

static void generate_repeat(struct generator * g, struct node * p, int atleast_case)
{   int keep_c = repeat_restore(g, p->left);
    wp(g, "~Mwhile(1) {~C~+", p);

    if (keep_c) wp(g, "~M~k~N", p);

    g->failure_label = new_label(g);
    g->failure_string = 0;
    generate(g, p->left);

    if (atleast_case) w(g, "~Mi--;~N");

    w(g, "~Mcontinue;~N");
    wsetl(g, g->failure_label);

    if (keep_c) wp(g, "~M~r~N", p);

    w(g, "~Mbreak;~N"
      "~}");
}

static void generate_atleast(struct generator * g, struct node * p)
{   w(g, "~{int i = "); generate_AE(g, p->AE); w(g, ";~N");
    {
        int a0 = g->failure_label;
        char * a1 = g->failure_string;

        generate_repeat(g, p, true);

        g->failure_label = a0;
        g->failure_string = a1;
    }
    w(g, "~Mif (i > 0) ~f~N"
      "~}");
}

static void generate_setmark(struct generator * g, struct node * p)
{   g->V[0] = p->name;
    wp(g, "~M~V0 = z->c;~C", p);
}

static void generate_tomark(struct generator * g, struct node * p)
{   g->S[0] = p->mode == m_forward ? ">" : "<";

    w(g, "~Mif (z->c ~S0 "); generate_AE(g, p->AE); w(g, ") ~f~N");
    w(g, "~Mz->c = "); generate_AE(g, p->AE); wp(g, ";~C", p);
}

static void generate_atmark(struct generator * g, struct node * p)
{
    w(g, "~Mif (z->c != "); generate_AE(g, p->AE); wp(g, ") ~f~C", p);
}


static void generate_hop(struct generator * g, struct node * p)
{   g->S[0] = p->mode == m_forward ? "+" : "-";

    w(g, "~{int c = z->c ~S0 "); generate_AE(g, p->AE); w(g, ";~N");

    g->S[0] = p->mode == m_forward ? "0" : "z->lb";

    wp(g, "~Mif (~S0 > c || c > z->l) ~f~N"
          "~Mz->c = c;~C"
          "~}", p);
}

static void generate_delete(struct generator * g, struct node * p)
{   wp(g, "~Mslice_del(z);~C", p);
}


static void generate_next(struct generator * g, struct node * p)
{   wp(g, "~M~l~N"
          "~M~i~C", p);
}

static void generate_tolimit(struct generator * g, struct node * p)
{   g->S[0] = p->mode == m_forward ? "" : "b";
    wp(g, "~Mz->c = z->l~S0;~C", p);
}

static void generate_atlimit(struct generator * g, struct node * p)
{   g->S[0] = p->mode == m_forward ? "" : "b";
    g->S[1] = p->mode == m_forward ? "<" : ">";
    wp(g, "~Mif (z->c ~S1 z->l~S0) ~f~C", p);
}

static void generate_leftslice(struct generator * g, struct node * p)
{   g->S[0] = p->mode == m_forward ? "bra" : "ket";
    wp(g, "~Mz->~S0 = z->c;~C", p);
}

static void generate_rightslice(struct generator * g, struct node * p)
{   g->S[0] = p->mode == m_forward ? "ket" : "bra";
    wp(g, "~Mz->~S0 = z->c;~C", p);
}

static void generate_assignto(struct generator * g, struct node * p)
{   g->V[0] = p->name;
    wp(g, "~M~V0 = assign_to(z, ~V0);~C", p);
}

static void generate_sliceto(struct generator * g, struct node * p)
{   g->V[0] = p->name;
    wp(g, "~M~V0 = slice_to(z, ~V0);~C", p);
}

static void generate_data_address(struct generator * g, struct node * p)
{
    symbol * b = p->literalstring;
    if (b != 0)
    {   wi(g, SIZE(b)); w(g, ", ");
        wlitref(g, b);
    } else
        wv(g, p->name);
}

static void generate_insert(struct generator * g, struct node * p, int style)
{
    int keep_c = style == c_attach;
    if (p->mode == m_backward) keep_c = !keep_c;
    if (keep_c) w(g, "~{int c = z->c;~N");
    wp(g, "~Minsert_~$(z, z->c, z->c, ", p);
    generate_data_address(g, p);
    wp(g, ");~C", p);
    if (keep_c) w(g, "~Mz->c = c;~N~}");
}

static void generate_assignfrom(struct generator * g, struct node * p)
{
    int keep_c = p->mode == m_forward; /* like 'attach' */
    if (keep_c) wp(g, "~{int c = z->c;~N"
                   "~Minsert_~$(z, z->c, z->l, ", p);
                else wp(g, "~Minsert_~$(z, z->lb, z->c, ", p);
    generate_data_address(g, p);
    wp(g, ");~C", p);
    if (keep_c) w(g, "~Mz->c = c;~N~}");
}

/* bugs marked <======= fixed 22/7/02. Similar fixes required for Java */

static void generate_slicefrom(struct generator * g, struct node * p)
{
/*  w(g, "~Mslice_from_s(z, ");   <============= bug! should be: */
    wp(g, "~Mslice_from_~$(z, ", p);
    generate_data_address(g, p);
    wp(g, ");~C", p);
}

static void generate_setlimit(struct generator * g, struct node * p)
{   wp(g, "~{~k~C"
              "~Mint m3;~N", p);
    generate(g, p->left);
    if (p->mode == m_forward) w(g, "~Mm3 = z->l - z->c; z->l = z->c;~N");
                         else w(g, "~Mm3 = z->lb; z->lb = z->c;~N");
    wp(g, "~M~r~N", p);
    {
        g->failure_string = p->mode == m_forward ? "z->l += m3;" :
                                                   "z->lb = m3;";
        generate(g, p->aux);
        wms(g, g->failure_string);
        w(g, "~N"
          "~}");
    }
}

/* There are bugs in this version
--static void generate_dollar(struct generator * g, struct node * p)
--{
--    g->V[0] = p->name;
--    g->failure_string = "* z = env;";
--    wp(g, "~{struct SN_env env = * z;~C"
--             "~Mz->p = ~V0;~N"
--             "~Mz->c = 0;~N"   <====== z->lb ought to be set to 0 as well
--             "~Mz->l = SIZE(z->p);~N", p);
--    generate(g, p->left);
--    wms(g, g->failure_string); <====== but string p->name may have a new address
--    w(g, "~N"
--      "~}");
--}
*/

static void generate_dollar(struct generator * g, struct node * p)
{
    int a0 = g->failure_label;
    char * a1 = g->failure_string;
    g->failure_label = new_label(g);
    g->failure_string = 0;

    g->V[0] = p->name;
    wp(g, "~{struct SN_env env = * z;~C"
             "~Mint failure = 1; /* assume failure */~N"
             "~Mz->p = ~V0;~N"
             "~Mz->lb = z->c = 0;~N"
             "~Mz->l = SIZE(z->p);~N", p);
    generate(g, p->left);
    w(g, "~Mfailure = 0; /* mark success */~N");
    wsetl(g, g->failure_label);
    g->V[0] = p->name; /* necessary */

    g->failure_label = a0;
    g->failure_string = a1;

    w(g, "~M~V0 = z->p;~N"
         "~M* z = env;~N"
         "~Mif (failure) ~f~N~}");
}

static void generate_integer_assign(struct generator * g, struct node * p, char * s)
{
    g->V[0] = p->name;
    g->S[0] = s;
    w(g, "~M~V0 ~S0 "); generate_AE(g, p->AE); w(g, ";~N");
}

static void generate_integer_test(struct generator * g, struct node * p, char * s)
{
    g->V[0] = p->name;
    g->S[0] = s;
    w(g, "~Mif (!(~V0 ~S0 "); generate_AE(g, p->AE); w(g, ")) ~f~N");
}

static void generate_call(struct generator * g, struct node * p)
{
    g->V[0] = p->name;
    wp(g, "~Mif (!~V0(z)) ~f~C", p);
}

static void generate_grouping(struct generator * g, struct node * p, int complement)
{
    struct grouping * q = p->name->grouping;
    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->S[1] = complement ? "out" : "in";
    g->V[0] = p->name;
    g->I[0] = q->smallest_ch;
    g->I[1] = q->largest_ch;
    if (q->no_gaps)
        w(g, "~Mif (!(~S1_range~S0(z, ~I0, ~I1))) ~f~N");
    else
        w(g, "~Mif (!(~S1_grouping~S0(z, ~V0, ~I0, ~I1))) ~f~N");
}

static void generate_namedstring(struct generator * g, struct node * p)
{
    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->V[0] = p->name;
    wp(g, "~Mif (!(eq_v~S0(z, ~V0))) ~f~C", p);
}

static void generate_literalstring(struct generator * g, struct node * p)
{   symbol * b = p->literalstring;
    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->I[0] = SIZE(b);
    g->L[0] = b;

    w(g, "~Mif (!(eq_s~S0(z, ~I0, ~L0))) ~f~N");
}

static void generate_define(struct generator * g, struct node * p)
{   struct name * q = p->name;
    g->next_label = 0;

    g->S[0] = q->type == t_routine ? "static" : "extern";
    g->V[0] = q;

    w(g, "~N~S0 int ~V0(struct SN_env * z) {~N~+");
    if (p->amongvar_needed) w(g, "~Mint among_var;~N");
    g->failure_string = 0;
    g->failure_label = x_return;
    generate(g, p->left);
    w(g, "~Mreturn 1;~N~}");
}

static void generate_substring(struct generator * g, struct node * p)
{
    struct among * x = p->among;

    g->S[0] = p->mode == m_forward ? "" : "_b";
    g->I[0] = x->number;
    g->I[1] = x->literalstring_count;

    if (x->command_count == 0 && x->starter == 0)
        wp(g, "~Mif (!(find_among~S0(z, a_~I0, ~I1))) ~f~C", p);
    else
        wp(g, "~Mamong_var = find_among~S0(z, a_~I0, ~I1);~C"
              "~Mif (!(among_var)) ~f~N", p);
}

static void generate_among(struct generator * g, struct node * p)
{
    struct among * x = p->among;
    int case_number = 1;

    if (x->substring == 0) generate_substring(g, p);
    if (x->command_count == 0 && x->starter == 0) return;

    unless (x->starter == 0) generate(g, x->starter);

    p = p->left;
    if (p != 0 && p->type != c_literalstring) p = p->right;
    w(g, "~Mswitch(among_var) {~N~+"
             "~Mcase 0: ~f~N");

    until (p == 0)
    {    if (p->type == c_bra && p->left != 0)
         {   g->I[0] = case_number++;
             w(g, "~Mcase ~I0:~N~+"); generate(g, p); w(g, "~Mbreak;~N~-");
         }
         p = p->right;
    }
    w(g, "~}");
}

static void generate_booltest(struct generator * g, struct node * p)
{
    g->V[0] = p->name;
    wp(g, "~Mif (!(~V0)) ~f~C", p);
}

static void generate_false(struct generator * g, struct node * p)
{
    wp(g, "~M~f~C", p);
}

static void generate_debug(struct generator * g, struct node * p)
{
    g->I[0] = g->debug_count++;
    g->I[1] = p->line_number;
    wp(g, "~Mdebug(z, ~I0, ~I1);~C", p);

}

static void generate(struct generator * g, struct node * p)
{
    int a0 = g->failure_label;
    char * a1 = g->failure_string;

    switch (p->type)
    {
        case c_define:        generate_define(g, p); break;
        case c_bra:           generate_bra(g, p); break;
        case c_and:           generate_and(g, p); break;
        case c_or:            generate_or(g, p); break;
        case c_backwards:     generate_backwards(g, p); break;
        case c_not:           generate_not(g, p); break;
        case c_set:           generate_set(g, p); break;
        case c_unset:         generate_unset(g, p); break;
        case c_try:           generate_try(g, p); break;
        case c_fail:          generate_fail(g, p); break;
        case c_reverse:
        case c_test:          generate_test(g, p); break;
        case c_do:            generate_do(g, p); break;
        case c_goto:          generate_GO(g, p, 1); break;
        case c_gopast:        generate_GO(g, p, 0); break;
        case c_repeat:        generate_repeat(g, p, false); break;
        case c_loop:          generate_loop(g, p); break;
        case c_atleast:       generate_atleast(g, p); break;
        case c_setmark:       generate_setmark(g, p); break;
        case c_tomark:        generate_tomark(g, p); break;
        case c_atmark:        generate_atmark(g, p); break;
        case c_hop:           generate_hop(g, p); break;
        case c_delete:        generate_delete(g, p); break;
        case c_next:          generate_next(g, p); break;
        case c_tolimit:       generate_tolimit(g, p); break;
        case c_atlimit:       generate_atlimit(g, p); break;
        case c_leftslice:     generate_leftslice(g, p); break;
        case c_rightslice:    generate_rightslice(g, p); break;
        case c_assignto:      generate_assignto(g, p); break;
        case c_sliceto:       generate_sliceto(g, p); break;
        case c_assign:        generate_assignfrom(g, p); break;
        case c_insert:
        case c_attach:        generate_insert(g, p, p->type); break;
        case c_slicefrom:     generate_slicefrom(g, p); break;
        case c_setlimit:      generate_setlimit(g, p); break;
        case c_dollar:        generate_dollar(g, p); break;
        case c_mathassign:    generate_integer_assign(g, p, "="); break;
        case c_plusassign:    generate_integer_assign(g, p, "+="); break;
        case c_minusassign:   generate_integer_assign(g, p, "-="); break;
        case c_multiplyassign:generate_integer_assign(g, p, "*="); break;
        case c_divideassign:  generate_integer_assign(g, p, "/="); break;
        case c_eq:            generate_integer_test(g, p, "=="); break;
        case c_ne:            generate_integer_test(g, p, "!="); break;
        case c_gr:            generate_integer_test(g, p, ">"); break;
        case c_ge:            generate_integer_test(g, p, ">="); break;
        case c_ls:            generate_integer_test(g, p, "<"); break;
        case c_le:            generate_integer_test(g, p, "<="); break;
        case c_call:          generate_call(g, p); break;
        case c_grouping:      generate_grouping(g, p, false); break;
        case c_non:           generate_grouping(g, p, true); break;
        case c_name:          generate_namedstring(g, p); break;
        case c_literalstring: generate_literalstring(g, p); break;
        case c_among:         generate_among(g, p); break;
        case c_substring:     generate_substring(g, p); break;
        case c_booltest:      generate_booltest(g, p); break;
        case c_false:         generate_false(g, p); break;
        case c_true:          break;
        case c_debug:         generate_debug(g, p); break;
        default: fprintf(stderr, "%d encountered\n", p->type);
                 exit(1);
    }

    g->failure_label = a0;
    g->failure_string = a1;

}

static void generate_start_comment(struct generator * g)
{
    w(g, "~N/* This file was generated automatically by the Snowball to ANSI C compiler */~N");
}

static void generate_head(struct generator * g)
{
    w(g, "~N#include \"header.h\"~N~N");
}

static void generate_routine_headers(struct generator * g)
{   struct name * q = g->analyser->names;
    until (q == 0)
    {   g->V[0] = q;
        switch (q->type)
        {   case t_routine:  g->S[0] = "static"; goto label0;
            case t_external: g->S[0] = "extern";
            label0:
                w(g, "~S0 int ~W0(struct SN_env * z);~N");
        }
        q = q->next;
    }
}

static void generate_among_table(struct generator * g, struct among * x)
{
    struct amongvec * v = x->b;

    g->I[0] = x->number;

    {   int i;
        for (i = 0; i < x->literalstring_count; i++)

        {   g->I[1] = i;
            g->I[2] = v->size;
            g->L[0] = v->b;
            unless (v->size == 0)
                w(g, "static symbol s_~I0_~I1[~I2] = ~A0;~N");
            v++;
        }
    }

    g->I[1] = x->literalstring_count;
    w(g, "~N~Mstatic struct among a_~I0[~I1] =~N{~N");

    v = x->b;
    {   int i;
        for (i = 0; i < x->literalstring_count; i++)

        {   g->I[1] = i;
            g->I[2] = v->size;
            g->I[3] = v->i;
            g->I[4] = v->result;
            g->S[0] = i < x->literalstring_count - 1 ? "," : "";

            w(g, "/*~J1 */ { ~I2, ");
            if (v->size == 0) w(g, "0,");
                         else w(g, "s_~I0_~I1,");
            w(g, " ~I3, ~I4, ");
            if (v->function == 0) w(g, "0"); else
                                  wvn(g, v->function);
            w(g, "}~S0~N");
            v++;
        }
    }
    w(g, "};~N~N");
}

static void generate_amongs(struct generator * g)
{   struct among * x = g->analyser->amongs;
    until (x == 0)
    {   generate_among_table(g, x);
        x = x->next;
    }
}

static void set_bit(symbol * b, int i) { b[i/8] |= 1 << i%8; }

static int bit_is_set(symbol * b, int i) { return b[i/8] & 1 << i%8; }

static void generate_grouping_table(struct generator * g, struct grouping * q)
{
    int range = q->largest_ch - q->smallest_ch + 1;
    int size = (range + 7)/ 8;  /* assume 8 bits per symbol */
    symbol * b = q->b;
    symbol * map = create_b(size);
    int i;
    for (i = 0; i < size; i++) map[i] = 0;

    for (i = 0; i < SIZE(b); i++) set_bit(map, b[i] - q->smallest_ch);

    q->no_gaps = true;
    for (i = 0; i < range; i++) unless (bit_is_set(map, i)) q->no_gaps = false;

    unless (q->no_gaps)
    {   g->V[0] = q->name;

        w(g, "static unsigned char ~V0[] = { ");
        for (i = 0; i < size; i++)
        {    wi(g, map[i]);
             if (i < size - 1) w(g, ", ");
        }
        w(g, " };~N~N");
    }
    lose_b(map);
}

static void generate_groupings(struct generator * g)
{   struct grouping * q = g->analyser->groupings;
    until (q == 0)
    {   generate_grouping_table(g, q);
        q = q->next;
    }
}

static void generate_create(struct generator * g)
{
    int * p = g->analyser->name_count;
    g->I[0] = p[t_string];
    g->I[1] = p[t_integer];
    g->I[2] = p[t_boolean];
    w(g, "~N"
         "extern struct SN_env * ~pcreate_env(void) { return SN_create_env(~I0, ~I1, ~I2); }"
         "~N");
}

static void generate_close(struct generator * g)
{
    w(g, "~Nextern void ~pclose_env(struct SN_env * z) { SN_close_env(z); }~N~N");
}

static void generate_create_and_close_templates(struct generator * g) {
    w(g, "~N"
         "extern struct SN_env * ~pcreate_env(void);~N"
         "extern void ~pclose_env(struct SN_env * z);~N~N");
}

static void generate_header_file(struct generator * g)
{
    struct name * q = g->analyser->names;
    char * vp = g->options->variables_prefix;
    g->S[0] = vp;

    w(g, "~N"
         "#ifdef __cplusplus~N"
         "extern \"C\" {~N"
         "#endif~N");            /* for C++ */


    generate_create_and_close_templates(g);
    until (q == 0)
    {   g->V[0] = q;
        switch (q->type)
        {
            case t_external:
                w(g, "extern int ~W0(struct SN_env * z);~N");
                break;
            case t_string:  g->S[1] = "S"; goto label0;
            case t_integer: g->S[1] = "I"; goto label0;
            case t_boolean: g->S[1] = "B";
            label0:
                if (vp)
                {   g->I[0] = q->count;
                    w(g, "#define ~S0");
                    str_append_b(g->outbuf, q->b);
                    w(g, " (~S1[~I0])~N");
                }
                break;
        }
        q = q->next;
    }

    w(g, "~N"
         "#ifdef __cplusplus~N"
         "}~N"
         "#endif~N");            /* for C++ */

    w(g, "~N");
}

extern void generate_program_c(struct generator * g)
{
    g->outbuf = str_new();
    generate_start_comment(g);
    generate_head(g);
    generate_routine_headers(g);
    generate_create_and_close_templates(g);
    generate_amongs(g);
    generate_groupings(g);
    g->declarations = g->outbuf;
    g->outbuf = str_new();
    g->literalstring_count = 0;
    {   struct node * p = g->analyser->program;
        until (p == 0) { generate(g, p); p = p->right; }
    }
    generate_create(g);
    generate_close(g);
    output_str(g->options->output_c, g->declarations);
    str_delete(g->declarations);
    output_str(g->options->output_c, g->outbuf);
    str_clear(g->outbuf);

    generate_start_comment(g);
    generate_header_file(g);
    output_str(g->options->output_h, g->outbuf);
    str_delete(g->outbuf);
}

extern struct generator * create_generator_c(struct analyser * a, struct options * o)
{   NEW(generator, g);
    g->analyser = a;
    g->options = o;
    g->margin = 0;
    g->debug_count = 0;
    g->line_count = 0;
    return g;
}

extern void close_generator_c(struct generator * g)
{
    FREE(g);
}

