/* ----------------------------------------------------------------------- */
/* J-Source Version 7 - COPYRIGHT 1993 Iverson Software Inc.               */
/* 33 Major Street, Toronto, Ontario, Canada, M5S 2K9, (416) 925 6096      */
/*                                                                         */
/* J-Source is provided "as is" without warranty of any kind.              */
/*                                                                         */
/* J-Source Version 7 license agreement:  You may use, copy, and           */
/* modify the source.  You have a non-exclusive, royalty-free right        */
/* to redistribute source and executable files.                            */
/* ----------------------------------------------------------------------- */
/*                                                                         */
/* Parsing; see APL Dictionary, pp. 12-13 & 38.                            */

#include "j.h"
#include "p.h"
#include "d.h"

#if (SYS & SYS_PC+SYS_PCWIN+SYS_PC386)
#define NDEPTH          175
#endif
#ifndef NDEPTH
#define NDEPTH          512
#endif

static I depth;
static A selfv;


F1(self1){A z;
 RZ(breaker());
 ASSERT(NDEPTH>++depth,EVLIMIT); z=df1(  w,selfv); --depth;
 R z;
}

F2(self2){A z;
 RZ(breaker());
 ASSERT(NDEPTH>++depth,EVLIMIT); z=df2(a,w,selfv); --depth;
 R z;
}

static DF1(dfs1){A oself=selfv,z; z=df1(  w,selfv=self); selfv=oself; R z;}

static DF2(dfs2){A oself=selfv,z; z=df2(a,w,selfv=self); selfv=oself; R z;}

DF2(unquote){A fs,z,n,g,m;B b;DC dc;
 RZ(breaker());
 n=VAV(self)->f;
 if(b=stname(n,&m,&g)){
  ASSERT(m, EVVALUE);
  g=stfind(g); ASSERT(g,EVVALUE);
  fs=srd(m,g); ASSERT(fs,EVVALUE);
 }else RZ(fs=symbrd(n));
 ASSERT(AT(self)==AT(fs),EVDOMAIN);
 ASSERT(NDEPTH>++depth,EVLIMIT);
 if(b){dc=debadd(DCNAME); dc->m=n; dc->p=global; global=g;}
 z=a?dfs2(a,w,fs):dfs1(w,fs);
 if(b){global=dc->p; debz();}
 --depth;
 R z;
}


static ACTION(monad){R dfs1(stack[e],stack[b]);}

static ACTION(dyad ){R dfs2(stack[b],stack[e],stack[e-1]);}

static ACTION(adv  ){R df1(stack[b],stack[e]);}

static ACTION(conj ){R df2(stack[b],stack[e],stack[e-1]);}

static ACTION(forkv){R folk(stack[b],stack[1+b],stack[e]);}

static ACTION(hookv){R hook(stack[b],stack[e]);}

static ACTION(formo){A f,g,h;
 f=stack[b]; g=stack[1+b]; h=stack[2+b];
 R b==e-1?hooko(f,g):forko(f,g,h);
}

static ACTION(curry){R advform(stack[b],stack[e]);}

static ACTION(punc ){R stack[e-1];}

static ACTION(move){A z;C c;
 z=stack[MAX(0,e)];
 R!(NAME&AT(z))||ASGN&AT(stack[b])?z:(c=cf(z),c==CALPHA||c==COMEGA)?symbrd(z):swap(z);
}

static F2(isg){R symbis(onm(a),ope(w),global);}

static F2(isl){R symbis(onm(a),ope(w),local );}

static ACTION(is){A n=stack[b],v=stack[e];C p=local&&*AV(stack[1+b]);
 RZ(NAME&AT(n) ? symbis(n,v,p?local:global) : rank2ex(n,v,0L,-1L,-1L,p?isl:isg));
 R v;
}


#define EDGE    (MARK+ASGN+LPAR)
#define NOTCONJ (NOUN+VERB+ADV)

PT cases[] = {
 EDGE,         VERB,      NOUN,      ANY,       monad, vmonad, cmonad, 1,2,1,
 EDGE+NOTCONJ, VERB,      VERB,      NOUN,      monad, vmonad, cmonad, 2,3,2,
 EDGE+NOTCONJ, NOUN,      VERB,      NOUN,      dyad,  vdyad,  cdyad,  1,3,2,
 EDGE+NOTCONJ, NOUN+VERB, ADV,       ANY,       adv,   vadv,   cadv,   1,2,1,
 EDGE+NOTCONJ, NOUN+VERB, CONJ,      NOUN+VERB, conj,  vconj,  cconj,  1,3,1,
 EDGE+NOTCONJ, VERB,      VERB,      VERB,      forkv, vforkv, cforkv, 1,3,1,
 EDGE,         VERB,      VERB,      ANY,       hookv, vhookv, chookv, 1,2,1,
 EDGE,         ADV+CONJ,  RHS,       ADV+CONJ,  formo, vformo, cformo, 1,3,1,
 EDGE,         ADV+CONJ,  ADV+CONJ,  ANY,       formo, vformo, cformo, 1,2,1,
 EDGE,         CONJ,      NOUN+VERB, ANY,       curry, vcurry, ccurry, 1,2,1,
 EDGE,         NOUN+VERB, CONJ,      ANY,       curry, vcurry, ccurry, 1,2,1,
 NAME+NOUN,    ASGN,      RHS,       ANY,       is,    vis,    vis,    0,2,1,
 LPAR,         RHS,       RPAR,      ANY,       punc,  vpunc,  vpunc,  0,2,0,
};

I ncases=(sizeof cases)/(sizeof cases[0]);

A parse(w) A w;{A*s,*stack,z;I b,*sp,*c,e,i,j,k,m,n;
 RZ(w);
 i=AN(w);
 stack=(A*)AV(w); n=m=i-4; asgn=0;
 RZ(sp=deba(stack,i));
 if(dbcheck()){jsignal(EVSTOP); debug(); debz(); R 0;}
 do{
  for(i=0;i<ncases;i++){
   c=cases[i].c; s=n+stack;
   if(*c++&AT(*s++)&&*c++&AT(*s++)&&*c++&AT(*s++)&&*c++&AT(*s++)) break;
  }
  if(i<ncases){
   b=cases[i].b; j=n+b;
   e=cases[i].e; k=n+e;
   asgn=is==cases[i].f;
   sp[k]=sp[n+cases[i].k];
   sitop->n=k; /* current location in token array */
   stack[k]=(cases[i].f)(j,k,stack);
   if(!stack[k]){debug(); debz(); R 0;}
   DO(b,stack[--k]=stack[--j];sp[k]=sp[j];); n=k;
  }else{
   sp[MAX(0,n-1)]=sp[MAX(0,m-1)];stack[n-1]=move(n,m-1,stack);
   if(!stack[n-1]){debz(); R 0;}
   n-=0<m--;
  }
 } while(0<=m);
 z=stack[1+n];
 if(!(AT(z)&MARK+RHS&&AT(stack[2+n])&MARK)){jsignal(EVSYNTAX); debug(); debz(); R 0;}
 debz();
 R z;
}