erasure.c

/***************************************
  $Header$

  Handle si, sa, su 
  ***************************************/

/* COPYRIGHT */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "nodes.h"
#include "rpc2x_act.tab.h"
#include "functions.h"

/*++++++++++++++++++++++++++++++
  ++++++++++++++++++++++++++++++*/

static void
handle_si(TreeNode *toks)
{
  TreeNode *x, *y, *nt, *z;
  TreeNode *ntt, *t;
  int require, si_got;

  for (x = toks->next;
       x != toks;
       x = nt) {

    nt = x->next;

    if (x->type == N_CMAVO &&
        x->data.cmavo.selmao == SI) {

      y = x->prev;

      if (y == toks) {
        fprintf(stderr, "Unmatched SI at start of input, line %d column %d\n",
                x->start_line, x->start_column);
        continue;
      }

      require = 1;

      switch (y->type) {
        case N_ZOI:
          require = 4;
          break;
        case N_ZO:
          require = 2;
          break;
        case N_LOhU:
          require = 3;
          break;
        case N_BRIVLA:
        case N_CMAVO:
        case N_CMENE:
          require = 1;
          break;
        case N_BROKEN_ERASURE:
          require = y->data.erasure.defects;
          break;
        default:
          fprintf(stderr, "Unrecognized token type %d before SI\n", y->type);
          fflush(stderr);
          assert(0);
      }

      z = x->next;
      si_got = 1;

      while ((si_got < require) &&
             (z != toks)) {
        if ((z->type == N_CMAVO) &&
            (z->data.cmavo.selmao == SI)) {
          si_got ++;
          z = z->next;
        } else {
          break;
        }
      }

      if (si_got < require) {
        y->type = N_BROKEN_ERASURE;
        y->data.erasure.defects = require - si_got;
      } else {
        delete_node(y);
      }

      for (t = x; t != z; t = ntt) {
        ntt = t->next;
        delete_node(t);
      }

      nt = z;

    }        
  }
}

/*++++++++++++++++++++++++++++++
  Handle the 'sa' erasure cmavo.  The definition this is working to is to erase
  back to something in the same selma'o as the word which follows.  If this
  hits the start of the text, erase everything up to the sa.
  ++++++++++++++++++++++++++++++*/

static void
handle_sa(TreeNode *toks)
{
  TreeNode *x, *y, *nt;

  for (x = toks->next;
       x != toks;
       x = nt) {

    nt = x->next;

    /*
       If x is last token, no following token to determine the type of what to
       erase back to.  In this case, the SA is ignored (which will cause a
       parse error later.) The alternative is to treat it as erasing the entire
       text, which seems heavy-handed.
       */

    if (nt == toks) break;

    if ((x->type != N_CMAVO) ||
        (x->data.cmavo.selmao != SA)) continue;

    for (y = x->prev; y != toks; y = y->prev) {
      if ((y->type == nt->type) &&
          (((y->type == N_CMAVO) && (y->data.cmavo.selmao == nt->data.cmavo.selmao)) ||
           (y->type != N_CMAVO))) {
        break;
      }      
    }

    if (y == toks) y = toks->next;

    while (y != nt) {
      TreeNode *ntt = y->next;
      delete_node(y);
      y = ntt;
    }
  }
}

/*++++++++++++++++++++++++++++++
NIhO, LU, TUhE, and TO.
  ++++++++++++++++++++++++++++++*/

static void
handle_su(TreeNode *toks)
{
  TreeNode *x, *y, *nt;

  for (x = toks->next;
       x != toks;
       x = nt) {

    nt = x->next;

    if ((x->type == N_CMAVO) &&
        (x->data.cmavo.selmao == SU)) {

      if ((nt != toks) &&
          (nt->type == N_CMAVO) &&
          (nt->data.cmavo.selmao == SU)) {
        /* double SU, delete all text up to date */
        
        TreeNode *u, *nu, *ntt;
        ntt = nt->next;
        for (u = toks->next; u != ntt; u = nu) {
          nu = u->next;
          delete_node(u);
        }
        nt = ntt;
        
      } else {
        /* single SU */
        for (y = x->prev; y != toks; y = y->prev) {
          if ((y->type == N_CMAVO) &&
              ((y->data.cmavo.selmao == NIhO) ||
               (y->data.cmavo.selmao == LU) ||
               (y->data.cmavo.selmao == TUhE) ||
               (y->data.cmavo.selmao == TO))) {
            break;
          }      
        }

        if (y == toks) y = toks->next;

        while (y != nt) {
          TreeNode *ntt = y->next;
          delete_node(y);
          y = ntt;
        }
      }
    }
  }
}

  
/*++++++++++++++++++++++++++++++
  ++++++++++++++++++++++++++++++*/

void
do_erasures(TreeNode *toks)
{
  handle_si(toks);
  handle_sa(toks);
  handle_su(toks);
}