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Diffstat (limited to 'z09.c')
| -rw-r--r-- | z09.c | 294 |
1 files changed, 294 insertions, 0 deletions
@@ -0,0 +1,294 @@ +/*@z09.c:Closure Expansion:SearchEnv()@***************************************/ +/* */ +/* THE LOUT DOCUMENT FORMATTING SYSTEM (VERSION 3.17) */ +/* COPYRIGHT (C) 1991, 1999 Jeffrey H. Kingston */ +/* */ +/* Jeffrey H. Kingston (jeff@cs.usyd.edu.au) */ +/* Basser Department of Computer Science */ +/* The University of Sydney 2006 */ +/* AUSTRALIA */ +/* */ +/* This program 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 2, or (at your option) */ +/* any later version. */ +/* */ +/* This program 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 this program; if not, write to the Free Software */ +/* Foundation, Inc., 59 Temple Place, Suite 330, Boston MA 02111-1307 USA */ +/* */ +/* FILE: z09.c */ +/* MODULE: Closure Expansion */ +/* EXTERNS: SearchEnv(), SetEnv(), AttachEnv(), GetEnv(), */ +/* DetachEnv(), ClosureExpand() */ +/* */ +/*****************************************************************************/ +#include "externs.h" + + +/*****************************************************************************/ +/* */ +/* OBJECT SearchEnv(env, sym) */ +/* */ +/* Search environment env for a symbol such that actual() == sym. */ +/* */ +/*****************************************************************************/ + +OBJECT SearchEnv(OBJECT env, OBJECT sym) +{ OBJECT link, y; + debug2(DCE, DD, "[ SearchEnv(%s, %s)", EchoObject(env), SymName(sym)); + for(;;) + { + debug1(DCE, DDD, " searching env %s", EchoObject(env)); + assert( env != nilobj && type(env) == ENV, "SearchEnv: env!" ); + if( Down(env) == env ) + { debug0(DCE, DD, "] SearchEnv returning <nilobj>"); + return nilobj; + } + Child(y, Down(env)); + assert( type(y) == CLOSURE, "SearchEnv: type(y) != CLOSURE!" ); + if( actual(y) == sym ) + { debug1(DCE, DD, "] SearchEnv returning %s", EchoObject(y)); + return y; + } + assert( LastDown(y) != y, "SearchEnv: LastDown(y) == y!" ); + link = LastDown(env) != Down(env) ? LastDown(env) : LastDown(y); + Child(env, link); + } +} /* end SearchEnv */ + + +/*@::SetEnv(), AttachEnv(), GetEnv(), DetachEnv()@****************************/ +/* */ +/* OBJECT SetEnv(x, y) */ +/* */ +/* Create a new environment containing x and possibly y. */ +/* */ +/*****************************************************************************/ + +OBJECT SetEnv(OBJECT x, OBJECT y) +{ OBJECT res; + debug1(DCE, DD, "SetEnv( x, %s ), x =", EchoObject(y)); + ifdebug(DCE, DD, DebugObject(x)); + assert( x!=nilobj && type(x)==CLOSURE, "SetEnv: x==nilobj or not CLOSURE!" ); + assert( y==nilobj || type(y)==ENV, "SetEnv: y!=nilobj && type(y) != ENV!" ); + New(res, ENV); Link(res, x); + if( y != nilobj ) Link(res, y); + debug1(DCE, DD, "SetEnv returning %s", EchoObject(res)); + return res; +} /* end SetEnv */ + + +/*****************************************************************************/ +/* */ +/* AttachEnv(env, x) */ +/* */ +/* Attach environment env to CLOSURE x. */ +/* */ +/*****************************************************************************/ + +void AttachEnv(OBJECT env, OBJECT x) +{ debug2(DCE, DD, "AttachEnv( %s, %s )", EchoObject(env), EchoObject(x)); + assert( env != nilobj && type(env) == ENV, "AttachEnv: type(env) != ENV!" ); + assert( type(x) == CLOSURE || type(x) == ENV_OBJ, "AttachEnv: type(x)!" ); + Link(x, env); + debug0(DCE, DD, "AttachEnv returning."); +} /* end AttachEnv */ + + +/*****************************************************************************/ +/* */ +/* OBJECT GetEnv(x) */ +/* */ +/* Get from CLOSURE x the environment previously attached. */ +/* */ +/*****************************************************************************/ + +OBJECT GetEnv(OBJECT x) +{ OBJECT env; + assert( type(x) == CLOSURE, "GetEnv: type(x) != CLOSURE!" ); + assert( LastDown(x) != x, "GetEnv: LastDown(x) == x!" ); + Child(env, LastDown(x)); + assert( type(env) == ENV, "GetEnv: type(env) != ENV!" ); + return env; +} /* end GetEnv */ + + +/*****************************************************************************/ +/* */ +/* OBJECT DetachEnv(x) */ +/* */ +/* Detach from CLOSURE x the environment previously attached. */ +/* */ +/*****************************************************************************/ + +OBJECT DetachEnv(OBJECT x) +{ OBJECT env; + debug1(DCE, DD, "DetachEnv( %s )", EchoObject(x)); + assert( type(x) == CLOSURE, "DetachEnv: type(x) != CLOSURE!" ); + assert( LastDown(x) != x, "DetachEnv: LastDown(x) == x!" ); + Child(env, LastDown(x)); + DeleteLink(LastDown(x)); + assert( type(env) == ENV, "DetachEnv: type(env) != ENV!" ); + debug1(DCE, DD, "DetachEnv resturning %s", EchoObject(env)); + return env; +} /* end DetachEnv */ + + +/*@::ClosureExpand()@*********************************************************/ +/* */ +/* OBJECT ClosureExpand(x, env, crs_wanted, crs, res_env) */ +/* */ +/* Return expansion of closure x in environment env. */ +/* The body comes from the environment of x if x is a parameter, else from */ +/* the symbol table. The original x is pushed into the environments. */ +/* If crs_wanted and x has a tag, a cross-reference is added to crs. */ +/* */ +/*****************************************************************************/ + +OBJECT ClosureExpand(OBJECT x, OBJECT env, BOOLEAN crs_wanted, +OBJECT *crs, OBJECT *res_env) +{ OBJECT link, y, res, prnt_env, par, prnt; + debug3(DCE, D, "[ ClosureExpand( %s, %s, %s, crs, res_env )", + EchoObject(x), EchoObject(env), bool(crs_wanted)); + assert( type(x) == CLOSURE, "ClosureExpand given non-CLOSURE!"); + assert( predefined(actual(x)) == FALSE, "ClosureExpand given predefined!" ); + + /* add tag to x if needed but not provided; add cross-reference to crs */ + if( has_tag(actual(x)) ) CrossAddTag(x); + if( crs_wanted && has_tag(actual(x)) ) + { OBJECT tmp = CopyObject(x, no_fpos); AttachEnv(env, tmp); + y = CrossMake(actual(x), tmp, CROSS_TARG); + New(tmp, CROSS_TARG); actual(tmp) = y; Link(tmp, y); + if( *crs == nilobj ) New(*crs, CR_LIST); Link(*crs, tmp); + } + + /* case x is a parameter */ + res = *res_env = nilobj; + if( is_par(type(actual(x))) ) + { prnt = SearchEnv(env, enclosing(actual(x))); + if( prnt != nilobj ) + { + prnt_env = GetEnv(prnt); + for( link = Down(prnt); link != prnt; link = NextDown(link) ) + { Child(par, link); + if( type(par) == PAR && actual(par) == actual(x) ) + { assert( Down(par) != par, "ExpandCLosure: Down(par)!"); + Child(res, Down(par)); + if( dirty(enclosing(actual(par))) ) + { debug2(DSU, DD, "c %s %s", SymName(actual(par)), EchoObject(res)); + res = CopyObject(res, no_fpos); + } + else + { debug2(DCE, DDD, "l %s %s", + FullSymName(actual(par), AsciiToFull(".")), EchoObject(res)); + DeleteLink(Down(par)); + y = MakeWord(WORD, STR_NOCROSS, &fpos(res)); + Link(par, y); + } + ReplaceNode(res, x); + if( type(actual(x)) == RPAR && has_body(enclosing(actual(x))) ) + { debug0(DCR, DDD, " calling SetEnv from ClosureExpand (a)"); + *res_env = SetEnv(prnt, nilobj); DisposeObject(x); + } + else if( type(actual(x)) == NPAR && imports_encl(actual(x)) ) + { debug0(DCR, DDD, " calling SetEnv from ClosureExpand (x)"); + AttachEnv(env, x); + *res_env = SetEnv(x, nilobj); + } + else + { AttachEnv(env, x); + debug0(DCR, DDD, " calling SetEnv from ClosureExpand (b)"); + *res_env = SetEnv(x, prnt_env); + } + break; + } + } + } + else + { + /* fail only if there is no default value available */ + if( sym_body(actual(x)) == nilobj ) + { + debug3(DCE, D, "failing ClosureExpand( %s, crs, %s, %s, res_env )\n", + EchoObject(x), bool(crs_wanted), EchoObject(env)); + Error(9, 2, "no value for parameter %s of symbol %s:", WARN, &fpos(x), + SymName(actual(x)), SymName(enclosing(actual(x)))); + Error(9, 1, "symbol with import list misused", FATAL, &fpos(x)); + } + } + } + + /* case x is a user-defined symbol or default parameter */ + if( res == nilobj ) + { if( sym_body(actual(x)) == nilobj ) + res = MakeWord(WORD,STR_NOCROSS,&fpos(x)); + else res = CopyObject(sym_body(actual(x)), &fpos(x)); + ReplaceNode(res, x); AttachEnv(env, x); + debug0(DCR, DDD, " calling SetEnv from ClosureExpand (c)"); + *res_env = SetEnv(x, nilobj); + } + + assert( *res_env!=nilobj && type(*res_env)==ENV, "ClosureExpand: *res_env!"); + debug0(DCE, D, "] ClosureExpand returning, res ="); + ifdebug(DCE, D, DebugObject(res)); + debug1(DCE, D, " environment = %s", EchoObject(*res_env)); + return res; +} /* end ClosureExpand */ + + +/*@::ParameterCheck()@********************************************************/ +/* */ +/* OBJECT ParameterCheck(x, env) */ +/* */ +/* Check whether object x (which is an actual parameter that happens to be */ +/* a CLOSURE) has a value which is a simple word, and if so return a copy */ +/* of that word, else nilobj. */ +/* */ +/*****************************************************************************/ + +OBJECT ParameterCheck(OBJECT x, OBJECT env) +{ OBJECT link, y, res, prnt_env, par, prnt; + debug2(DCE, DD, "ParameterCheck(%s, %s)", EchoObject(x), EchoObject(env)); + assert( type(x) == CLOSURE, "ParameterCheck given non-CLOSURE!"); + + /* case x is a parameter */ + prnt = SearchEnv(env, enclosing(actual(x))); + if( prnt == nilobj ) + { debug0(DCE, DD, "ParameterCheck returning nilobj (prnt fail)"); + return nilobj; + } + prnt_env = GetEnv(prnt); + for( link = Down(prnt); link != prnt; link = NextDown(link) ) + { Child(par, link); + if( type(par) == PAR && actual(par) == actual(x) ) + { assert( Down(par) != par, "ParameterCheck: Down(par)!"); + Child(y, Down(par)); + res = is_word(type(y)) ? CopyObject(y, no_fpos) : nilobj; + debug1(DCE, DD, " ParameterCheck returning %s", EchoObject(res)); + return res; + } + } + + /* case x is a default parameter */ + y = sym_body(actual(x)); + if( y == nilobj ) + { res = nilobj; + } + else if( is_word(type(y)) ) + { res = CopyObject(y, &fpos(y)); + } + else if( type(y) == CLOSURE && is_par(type(actual(y))) ) + { res = ParameterCheck(y, prnt_env); + } + else + { res = nilobj; + } + debug1(DCE, DD, "ParameterCheck returning %s", EchoObject(res)); + return res; +} /* end ParameterCheck */ |