585 lines
12 KiB
Plaintext
585 lines
12 KiB
Plaintext
/*
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* (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
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*
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* This product is part of the Amsterdam Compiler Kit.
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*
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* Permission to use, sell, duplicate or disclose this software must be
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* obtained in writing. Requests for such permissions may be sent to
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*
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* Dr. Andrew S. Tanenbaum
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* Wiskundig Seminarium
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* Vrije Universiteit
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* Postbox 7161
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* 1007 MC Amsterdam
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* The Netherlands
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*
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*/
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/*
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* L L G E N
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*
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* An Extended LL(1) Parser Generator
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*
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* Author : Ceriel J.H. Jacobs
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*/
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/*
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* LLgen.g
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* Defines the grammar of LLgen.
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* Some routines that build the internal structure are also included
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*/
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{
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# include "types.h"
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# include "io.h"
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# include "extern.h"
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# include "assert.h"
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# include "cclass.h"
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# ifndef NORCSID
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static string rcsid = "$Header$";
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# endif
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p_mem alloc(), new_mem();
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string store();
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p_gram search();
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static int nparams; /* parameter count for nonterminals */
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static int acount; /* count #of global actions */
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static t_info term_info,
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link_info;
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static p_order order,
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maxorder;
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/* Here are defined : */
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extern a_init();
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STATIC p_order neworder();
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STATIC copyact();
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STATIC mkalt();
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STATIC mkterm();
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STATIC p_gram copyrule();
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/* and of course LLparse() */
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a_init() {
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term_info.i_esize = sizeof (t_term);
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term_info.i_incr = 50;
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link_info.i_esize = sizeof (t_link);
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link_info.i_incr = 50;
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name_init();
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}
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STATIC p_order
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neworder(index) {
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register p_order po;
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if ((po = order) == maxorder) {
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po = (p_order) alloc(20 * sizeof(*order));
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maxorder = po + 20;
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}
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order = po + 1;
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po->o_next = 0;
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po->o_index = index;
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if (porder) {
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porder->o_next = po;
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}
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else sorder = po;
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return po;
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}
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}
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%start LLparse, spec;
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spec : { acount = 0; }
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[ %persistent def ]*
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{ /*
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* Put an endmarker in temporary file
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*/
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fprintf(fact,"%c%c",'\0', '\0');
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}
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;
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def { register string p; }
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: rule
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/*
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* A grammar rule
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*/
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| C_TOKEN listel [ ',' listel ]* ';'
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/*
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* A token declaration
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*/
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| C_START C_IDENT
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{ p = store(lextoken.t_string); }
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',' C_IDENT ';'
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/*
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* A start symbol declaration
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*/
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{ /*
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* Put the declaration in the list
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* of start symbols
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*/
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register p_gram temp;
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register p_start ff;
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temp = search(NONTERM,lextoken.t_string,BOTH);
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ff = (p_start) alloc(sizeof(t_start));
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ff->ff_nont = g_getnont(temp);
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ff->ff_name = p;
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ff->ff_next = start;
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start = ff;
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}
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| C_LEXICAL C_IDENT
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{ if (!lexical) {
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lexical = store(lextoken.t_string);
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}
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else error(linecount,"Duplicate %%lexical");
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}
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';'
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/*
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* Declaration of a name for the lexical analyser.
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* May appear only once
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*/
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| action(0) { acount++; }
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/*
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* A global C-declaration
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*/
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| firsts
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/*
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* declarations for macros
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*/
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;
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listel : C_IDENT { search(TERMINAL,lextoken.t_string,ENTERING); }
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;
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rule { register p_nont p;
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p_gram rr;
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register p_gram temp;
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}
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: /*
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* grammar for a production rule
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*/
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C_IDENT { temp = search(NONTERM,lextoken.t_string,BOTH);
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p = &nonterms[g_getnont(temp)];
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if (p->n_rule) {
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error(linecount,
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"nonterminal %s already defined", lextoken.t_string);
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}
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/*
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* Remember the order in which the nonterminals
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* were defined. Code must be generated in that
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* order to keep track with the actions on the
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* temporary file
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*/
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porder = neworder(p - nonterms);
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p->n_count = acount;
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acount = 0;
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p->n_lineno = linecount;
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}
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[ params(2) { p->n_flags |= PARAMS;
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if (nparams > 15) {
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error(linecount,"Too many parameters");
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}
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else setntparams(p,nparams);
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}
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]?
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[ action(0) { p->n_flags |= LOCALS; }
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]?
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':' productions(&rr) ';'
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/*
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* Do not use p->n_rule now! The nonterms array
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* might have been re-allocated.
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*/
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{ nonterms[g_getnont(temp)].n_rule = rr;}
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;
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action(int n;)
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/*
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* The parameter n is non-zero when the opening and closing
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* bracket must be copied along with the action
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*/
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: '{' { copyact('{','}',n,0); }
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'}'
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;
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productions(p_gram *p;)
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/*
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* One or more alternatives
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*/
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{ p_gram prod;
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int conflres = 0;
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int t = 0;
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int haddefault = 0;
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t_gram alts[100];
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register p_gram p_alts = alts;
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int o_lc, n_lc;
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} :
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{ o_lc = linecount; }
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simpleproduction(p,&conflres)
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{ if (conflres & DEF) haddefault = 1; }
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[
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[ '|' { n_lc = linecount; }
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simpleproduction(&prod,&t)
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{ if (p_alts - alts >= 97) {
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error(n_lc,"Too many alternatives");
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p_alts = alts;
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}
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if (t & DEF) {
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if (haddefault) {
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error(n_lc,
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"More than one %%default in alternation");
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}
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haddefault = 1;
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}
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mkalt(*p,conflres,o_lc,p_alts++);
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o_lc = n_lc;
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conflres = t;
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t = 0;
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*p = prod;
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}
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]+ { if (conflres & ~DEF) {
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error(n_lc,
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"Resolver on last alternative not allowed");
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}
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mkalt(*p,conflres,n_lc,p_alts++);
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g_settype(p_alts,EORULE);
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*p = copyrule(alts,p_alts+1-alts);
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}
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{ if (conflres & ~DEF) {
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error(o_lc,
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"No alternation conflict resolver allowed here");
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}
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/*
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if (conflres & DEF) {
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error(o_lc,
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"No %%default allowed here");
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}
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*/
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}
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]
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;
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{
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STATIC
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mkalt(prod,condition,lc,res) p_gram prod; register p_gram res; {
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/*
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* Create an alternation and initialise it.
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*/
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register int hulp;
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register p_link l;
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l = (p_link) new_mem(&link_info);
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links = (p_link) link_info.i_ptr;
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hulp = l - links;
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l->l_rule = prod;
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l->l_flag = condition;
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g_setcont(res,hulp);
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g_settype(res,ALTERNATION);
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res->g_lineno = lc;
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}
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}
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simpleproduction(p_gram *p; register int *conflres;)
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{ t_gram rule[100];
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t_gram elem;
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register p_gram p_rule = rule;
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int cnt, kind;
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} :
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[ C_DEFAULT { *conflres = DEF; }
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]?
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[
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/*
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* Optional conflict reslover
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*/
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C_IF expr { *conflres |= COND; }
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| C_PREFER { *conflres |= PREFERING; }
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| C_AVOID { *conflres |= AVOIDING; }
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]?
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[ %persistent elem(&elem)
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{ if (p_rule - rule >= 98) {
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error(linecount,"Production too long");
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p_rule = rule;
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}
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kind = FIXED;
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cnt = 0;
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}
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[ repeats(&kind, &cnt)
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{ if (g_gettype(&elem) != TERM) {
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*p_rule = elem;
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g_settype(p_rule+1,EORULE);
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mkterm(copyrule(p_rule,2),
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0,
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p_rule->g_lineno,
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&elem);
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}
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}
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]? { if (g_gettype(&elem) == TERM) {
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register p_term q;
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q = &terms[g_getcont(&elem)];
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r_setkind(q,kind);
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r_setnum(q,cnt);
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if ((q->t_flags & RESOLVER) &&
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(kind == PLUS || kind == FIXED)) {
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error(linecount,
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"%%while not allowed in this term");
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}
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/*
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* A persistent fixed term is the same
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* as a non-persistent fixed term.
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* Should we complain?
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if ((q->t_flags & PERSISTENT) &&
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kind == FIXED) {
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error(linecount,
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"illegal %%persistent");
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}
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*/
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}
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*p_rule++ = elem;
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}
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]* { register p_term q;
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g_settype(p_rule,EORULE);
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*p = 0;
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if (g_gettype(&rule[0]) == TERM &&
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p_rule-rule == 1) {
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q = &terms[g_getcont(&rule[0])];
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if (r_getkind(q) == FIXED &&
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r_getnum(q) == 0) {
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*p = q->t_rule;
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}
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}
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if (!*p) *p = copyrule(rule,p_rule-rule+1);
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}
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;
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{
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STATIC
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mkterm(prod,flags,lc, result) p_gram prod; register p_gram result; {
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/*
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* Create a term, initialise it and return
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* a grammar element containing it
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*/
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register p_term q;
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unsigned hulp;
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q = (p_term) new_mem(&term_info);
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terms = (p_term) term_info.i_ptr;
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hulp = q - terms;
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q->t_rule = prod;
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q->t_contains = 0;
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q->t_flags = flags;
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g_settype(result,TERM);
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g_setcont(result,hulp);
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result->g_lineno = lc;
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}
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}
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elem (register p_gram pres;)
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{ register short t = 0;
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p_gram p1;
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int ln;
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p_gram pe;
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} :
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'[' { ln = linecount; }
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[ C_WHILE expr { t |= RESOLVER; }
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]?
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[ C_PERSISTENT { t |= PERSISTENT; }
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]?
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productions(&p1)
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']' {
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mkterm(p1,t,ln,pres);
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}
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C_IDENT { pe = search(UNKNOWN,lextoken.t_string,BOTH);
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*pres = *pe;
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}
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[ params(0) { if (nparams > 14) {
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error(linecount,"Too many parameters");
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} else g_setnpar(pres,nparams+1);
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if (g_gettype(pres) == TERMINAL) {
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error(linecount,
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"Terminal with parameters");
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}
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}
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]?
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| C_LITERAL { pe = search(LITERAL,lextoken.t_string,BOTH);
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*pres = *pe;
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}
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| { g_settype(pres,ACTION);
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pres->g_lineno = linecount;
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}
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action(1)
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;
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params(int n;)
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: '(' { copyact('(',')',n,0); }
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')'
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;
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expr : '(' { copyact('(',')',1,0); }
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')'
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;
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repeats(int *kind, *cnt;) { int t1 = 0; } :
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[
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'?' { *kind = OPT; }
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| [ '*' { *kind = STAR; }
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| '+' { *kind = PLUS; }
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]
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number(&t1)?
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{ if (t1 == 1) {
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t1 = 0;
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if (*kind == STAR) *kind = OPT;
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if (*kind == PLUS) *kind = FIXED;
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}
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}
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| number(&t1)
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] { *cnt = t1; }
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;
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number(int *t;)
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: C_NUMBER
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{ *t = lextoken.t_num;
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if (*t <= 0 || *t >= 8192) {
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error(linecount,"Illegal number");
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}
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}
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;
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firsts { register string p; }
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: C_FIRST C_IDENT
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{ p = store(lextoken.t_string); }
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',' C_IDENT ';'
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{ /*
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* Store this %first in the list belonging
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* to this input file
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*/
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p_gram temp;
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register p_first ff;
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temp = search(NONTERM,lextoken.t_string,BOTH);
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ff = (p_first) alloc(sizeof(t_first));
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ff->ff_nont = g_getnont(temp);
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ff->ff_name = p;
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ff->ff_next = pfile->f_firsts;
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pfile->f_firsts = ff;
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}
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;
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{
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STATIC
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copyact(ch1,ch2,flag,level) char ch1,ch2; {
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/*
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* Copy an action to file f. Opening bracket is ch1, closing bracket
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* is ch2.
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* If flag = 1, copy opening and closing parameters too.
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* If flag = 2, the copy is a parameter declaration copy.
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* Give an error message if not ending on a ';'
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*/
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register FILE *f;
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register ch; /* Current char */
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register match; /* used to read strings */
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int saved; /* save linecount */
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int semicolon = 0;
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f = fact;
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if (!level) {
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saved = linecount;
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nparams = 0; /* count comma's */
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fprintf(f,"%c# line %d \"%s\"\n", '\0', linecount,f_input);
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}
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if (level || flag == 1) putc(ch1,f);
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for (;;) {
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ch = input();
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if (ch == ch2) {
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if (!level) unput(ch);
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if (level || flag == 1) putc(ch,f);
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if ((!level) && flag == 2 && !semicolon) {
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error(linecount,"missing ';'");
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}
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return;
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}
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if (c_class[ch] != ISSPA) semicolon = 0;
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switch(ch) {
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case ')':
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case '}':
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case ']':
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error(linecount,"Parentheses mismatch");
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break;
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case '(':
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copyact('(',')',flag,level+1);
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continue;
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case '{':
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copyact('{','}',flag,level+1);
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continue;
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case '[':
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copyact('[',']',flag,level+1);
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continue;
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case '/':
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ch = input();
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unput(ch);
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if (ch == '*') {
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skipcomment(1);
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continue;
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}
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ch = '/';
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break;
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case ';':
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semicolon = 1;
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/* Fall through */
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case ',':
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if (!level) { /*
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* Only ','s and ';'s on the
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* outer level are counted
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*/
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nparams++;
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}
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break;
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case '\'':
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case '"' :
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/*
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* watch out for brackets in strings, they do not
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* count !
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*/
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match = ch;
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putc(ch,f);
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while((ch = input())) {
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if (ch == match) break;
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if (ch == '\\') {
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putc(ch,f);
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ch = input();
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}
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if (ch == '\n') {
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error(linecount,"newline in string");
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unput(match);
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}
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putc(ch,f);
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}
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if (ch == match) break;
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/* Fall through */
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case EOF :
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if (!level) error(saved,"Action does not terminate");
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return;
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}
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putc(ch,f);
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}
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}
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STATIC p_gram
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copyrule(p,length) register p_gram p; {
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/*
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* Returns a pointer to a grammar rule that was created in
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* p. The space pointed to by p can now be reused
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*/
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register p_gram t;
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p_gram rule;
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t = (p_gram) alloc((unsigned) length * sizeof(t_gram));
|
|
rule = t;
|
|
while (length--) {
|
|
*t++ = *p++;
|
|
}
|
|
return rule;
|
|
}
|
|
}
|