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#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#ifdef __COVERITY__
#define _Float128 long double
#define _Float64x long double
#define _Float64 double
#define _Float32x double
#define _Float32 float
#endif
/*
** This file contains all sources (including headers) to the LEMON
** LALR(1) parser generator. The sources have been combined into a
** single file to make it easy to include LEMON in the source tree
** and Makefile of another program.
**
** The author of this program disclaims copyright.
*/
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <inttypes.h>
#include <unistd.h> /* access() */
#define UNUSED(x) ( (void)(x) )
#ifndef __WIN32__
# if defined(_WIN32) || defined(WIN32)
# define __WIN32__
# endif
#endif
#if __GNUC__ > 2
#define NORETURN __attribute__ ((__noreturn__))
#else
#define NORETURN
#endif
/* #define PRIVATE static */
#define PRIVATE static
#ifdef TEST
#define MAXRHS 5 /* Set low to exercise exception code */
#else
#define MAXRHS 1000
#endif
void *msort(void *list, void **next, int(*cmp)(void *, void *));
static void memory_error() NORETURN;
/******** From the file "action.h" *************************************/
struct action *Action_new();
struct action *Action_sort();
void Action_add();
/********* From the file "assert.h" ************************************/
void myassert() NORETURN;
#ifndef NDEBUG
# define assert(X) if(!(X))myassert(__FILE__,__LINE__)
#else
# define assert(X)
#endif
/********** From the file "build.h" ************************************/
void FindRulePrecedences();
void FindFirstSets();
void FindStates();
void FindLinks();
void FindFollowSets();
void FindActions();
/********* From the file "configlist.h" *********************************/
void Configlist_init(/* void */);
struct config *Configlist_add(/* struct rule *, int */);
struct config *Configlist_addbasis(/* struct rule *, int */);
void Configlist_closure(/* void */);
void Configlist_sort(/* void */);
void Configlist_sortbasis(/* void */);
struct config *Configlist_return(/* void */);
struct config *Configlist_basis(/* void */);
void Configlist_eat(/* struct config * */);
void Configlist_reset(/* void */);
/********* From the file "error.h" ***************************************/
void ErrorMsg(const char *, int,const char *, ...);
/****** From the file "option.h" ******************************************/
struct s_options {
enum { OPT_FLAG=1, OPT_INT, OPT_DBL, OPT_STR,
OPT_FFLAG, OPT_FINT, OPT_FDBL, OPT_FSTR} type;
char *label;
void *arg;
const char *message;
};
int OptInit(/* char**,struct s_options*,FILE* */);
int OptNArgs(/* void */);
char *OptArg(/* int */);
void OptErr(/* int */);
void OptPrint(/* void */);
/******** From the file "parse.h" *****************************************/
void Parse(/* struct lemon *lemp */);
/********* From the file "plink.h" ***************************************/
struct plink *Plink_new(/* void */);
void Plink_add(/* struct plink **, struct config * */);
void Plink_copy(/* struct plink **, struct plink * */);
void Plink_delete(/* struct plink * */);
/********** From the file "report.h" *************************************/
void Reprint(/* struct lemon * */);
void ReportOutput(/* struct lemon * */);
void ReportTable(/* struct lemon * */);
void ReportHeader(/* struct lemon * */);
void CompressTables(/* struct lemon * */);
/********** From the file "set.h" ****************************************/
void SetSize(/* int N */); /* All sets will be of size N */
char *SetNew(/* void */); /* A new set for element 0..N */
void SetFree(/* char* */); /* Deallocate a set */
int SetAdd(/* char*,int */); /* Add element to a set */
int SetUnion(/* char *A,char *B */); /* A <- A U B, thru element N */
#define SetFind(X,Y) (X[Y]) /* True if Y is in set X */
/********** From the file "struct.h" *************************************/
/*
** Principal data structures for the LEMON parser generator.
*/
typedef enum {Bo_FALSE=0, Bo_TRUE} Boolean;
/* Symbols (terminals and nonterminals) of the grammar are stored
** in the following: */
struct symbol {
char *name; /* Name of the symbol */
int index; /* Index number for this symbol */
enum {
TERMINAL,
NONTERMINAL
} type; /* Symbols are all either TERMINALS or NTs */
struct rule *rule; /* Linked list of rules of this (if an NT) */
struct symbol *fallback; /* fallback token in case this token doesn't parse */
int prec; /* Precedence if defined (-1 otherwise) */
enum e_assoc {
LEFT,
RIGHT,
NONE,
UNK
} assoc; /* Associativity if predecence is defined */
char *firstset; /* First-set for all rules of this symbol */
Boolean lambda; /* True if NT and can generate an empty string */
char *destructor; /* Code which executes whenever this symbol is
** popped from the stack during error processing */
int destructorln; /* Line number of destructor code */
char *datatype; /* The data type of information held by this
** object. Only used if type==NONTERMINAL */
int dtnum; /* The data type number. In the parser, the value
** stack is a union. The .yy%d element of this
** union is the correct data type for this object */
};
/* Each production rule in the grammar is stored in the following
** structure. */
struct rule {
struct symbol *lhs; /* Left-hand side of the rule */
char *lhsalias; /* Alias for the LHS (NULL if none) */
int ruleline; /* Line number for the rule */
int nrhs; /* Number of RHS symbols */
struct symbol **rhs; /* The RHS symbols */
char **rhsalias; /* An alias for each RHS symbol (NULL if none) */
int line; /* Line number at which code begins */
char *code; /* The code executed when this rule is reduced */
struct symbol *precsym; /* Precedence symbol for this rule */
int index; /* An index number for this rule */
Boolean canReduce; /* True if this rule is ever reduced */
struct rule *nextlhs; /* Next rule with the same LHS */
struct rule *next; /* Next rule in the global list */
};
/* A configuration is a production rule of the grammar together with
** a mark (dot) showing how much of that rule has been processed so far.
** Configurations also contain a follow-set which is a list of terminal
** symbols which are allowed to immediately follow the end of the rule.
** Every configuration is recorded as an instance of the following: */
struct config {
struct rule *rp; /* The rule upon which the configuration is based */
int dot; /* The parse point */
char *fws; /* Follow-set for this configuration only */
struct plink *fplp; /* Follow-set forward propagation links */
struct plink *bplp; /* Follow-set backwards propagation links */
struct state *stp; /* Pointer to state which contains this */
enum {
COMPLETE, /* The status is used during followset and */
INCOMPLETE /* shift computations */
} status;
struct config *next; /* Next configuration in the state */
struct config *bp; /* The next basis configuration */
};
/* Every shift or reduce operation is stored as one of the following */
struct action {
struct symbol *sp; /* The look-ahead symbol */
enum e_action {
SHIFT,
ACCEPT,
REDUCE,
ERROR,
CONFLICT, /* Was a reduce, but part of a conflict */
SH_RESOLVED, /* Was a shift. Precedence resolved conflict */
RD_RESOLVED, /* Was reduce. Precedence resolved conflict */
NOT_USED /* Deleted by compression */
} type;
union {
struct state *stp; /* The new state, if a shift */
struct rule *rp; /* The rule, if a reduce */
} x;
struct action *next; /* Next action for this state */
struct action *collide; /* Next action with the same hash */
};
/* Each state of the generated parser's finite state machine
** is encoded as an instance of the following structure. */
struct state {
struct config *bp; /* The basis configurations for this state */
struct config *cfp; /* All configurations in this set */
int index; /* Sequencial number for this state */
struct action *ap; /* Array of actions for this state */
int nTknAct, nNtAct; /* Number of actions on terminals and nonterminals */
int iTknOfst, iNtOfst; /* yy_action[] offset for terminals and nonterms */
int iDflt; /* Default action */
};
#define NO_OFFSET (-2147483647)
/* A followset propagation link indicates that the contents of one
** configuration followset should be propagated to another whenever
** the first changes. */
struct plink {
struct config *cfp; /* The configuration to which linked */
struct plink *next; /* The next propagate link */
};
/* The state vector for the entire parser generator is recorded as
** follows. (LEMON uses no global variables and makes little use of
** static variables. Fields in the following structure can be thought
** of as begin global variables in the program.) */
struct lemon {
struct state **sorted; /* Table of states sorted by state number */
struct rule *rule; /* List of all rules */
int nstate; /* Number of states */
int nrule; /* Number of rules */
int nsymbol; /* Number of terminal and nonterminal symbols */
int nterminal; /* Number of terminal symbols */
struct symbol **symbols; /* Sorted array of pointers to symbols */
int errorcnt; /* Number of errors */
struct symbol *errsym; /* The error symbol */
char *name; /* Name of the generated parser */
char *arg; /* Declaration of the 3th argument to parser */
char *tokentype; /* Type of terminal symbols in the parser stack */
char *vartype; /* The default type of non-terminal symbols */
char *start; /* Name of the start symbol for the grammar */
char *stacksize; /* Size of the parser stack */
char *include; /* Code to put at the start of the C file */
int includeln; /* Line number for start of include code */
char *error; /* Code to execute when an error is seen */
int errorln; /* Line number for start of error code */
char *overflow; /* Code to execute on a stack overflow */
int overflowln; /* Line number for start of overflow code */
char *failure; /* Code to execute on parser failure */
int failureln; /* Line number for start of failure code */
char *accept; /* Code to execute when the parser excepts */
int acceptln; /* Line number for the start of accept code */
char *extracode; /* Code appended to the generated file */
int extracodeln; /* Line number for the start of the extra code */
char *tokendest; /* Code to execute to destroy token data */
int tokendestln; /* Line number for token destroyer code */
char *vardest; /* Code for the default non-terminal destructor */
int vardestln; /* Line number for default non-term destructor code*/
char *filename; /* Name of the input file */
char *tmplname; /* Name of the template file */
char *outname; /* Name of the current output file */
char *tokenprefix; /* A prefix added to token names in the .h file */
int nconflict; /* Number of parsing conflicts */
int tablesize; /* Size of the parse tables */
int basisflag; /* Print only basis configurations */
int has_fallback; /* True if any %fallback is seen in the grammer */
char *argv0; /* Name of the program */
};
#define MemoryCheck(X) if((X)==0){ \
memory_error(); \
}
/**************** From the file "table.h" *********************************/
/*
** All code in this file has been automatically generated
** from a specification in the file
** "table.q"
** by the associative array code building program "aagen".
** Do not edit this file! Instead, edit the specification
** file, then rerun aagen.
*/
/*
** Code for processing tables in the LEMON parser generator.
*/
/* Routines for handling a strings */
char *Strsafe();
void Strsafe_init(/* void */);
int Strsafe_insert(/* char * */);
char *Strsafe_find(/* char * */);
/* Routines for handling symbols of the grammar */
struct symbol *Symbol_new();
int Symbolcmpp(/* struct symbol **, struct symbol ** */);
void Symbol_init(/* void */);
int Symbol_insert(/* struct symbol *, char * */);
struct symbol *Symbol_find(/* char * */);
struct symbol *Symbol_Nth(/* int */);
int Symbol_count(/* */);
int State_count(void);
struct symbol **Symbol_arrayof(/* */);
/* Routines to manage the state table */
int Configcmp(/* struct config *, struct config * */);
struct state *State_new();
void State_init(/* void */);
int State_insert(/* struct state *, struct config * */);
struct state *State_find(/* struct config * */);
struct state **State_arrayof(/* */);
/* Routines used for efficiency in Configlist_add */
void Configtable_init(/* void */);
int Configtable_insert(/* struct config * */);
struct config *Configtable_find(/* struct config * */);
void Configtable_clear(/* int(*)(struct config *) */);
/****************** From the file "action.c" *******************************/
/*
** Routines processing parser actions in the LEMON parser generator.
*/
/* Allocate a new parser action */
struct action *Action_new(){
static struct action *freelist = NULL;
struct action *new;
if( freelist==NULL ){
int i;
int amt = 100;
freelist = (struct action *)malloc( sizeof(struct action)*amt );
if( freelist==0 ){
fprintf(stderr,"Unable to allocate memory for a new parser action.");
exit(1);
}
for(i=0; i<amt-1; i++) freelist[i].next = &freelist[i+1];
freelist[amt-1].next = 0;
}
new = freelist;
freelist = freelist->next;
return new;
}
/* Compare two actions */
static int actioncmp(ap1,ap2)
struct action *ap1;
struct action *ap2;
{
int rc;
rc = ap1->sp->index - ap2->sp->index;
if( rc==0 ) rc = (int)ap1->type - (int)ap2->type;
if( rc==0 ){
assert( ap1->type==REDUCE || ap1->type==RD_RESOLVED || ap1->type==CONFLICT);
assert( ap2->type==REDUCE || ap2->type==RD_RESOLVED || ap2->type==CONFLICT);
rc = ap1->x.rp->index - ap2->x.rp->index;
}
return rc;
}
/* Sort parser actions */
struct action *Action_sort(ap)
struct action *ap;
{
ap = (struct action *)msort(ap,(void **)&ap->next,actioncmp);
return ap;
}
void Action_add(app,type,sp,arg)
struct action **app;
enum e_action type;
struct symbol *sp;
void *arg;
{
struct action *new;
new = Action_new();
new->next = *app;
*app = new;
new->type = type;
new->sp = sp;
if( type==SHIFT ){
new->x.stp = (struct state *)arg;
}else{
new->x.rp = (struct rule *)arg;
}
}
/********************** New code to implement the "acttab" module ***********/
/*
** This module implements routines use to construct the yy_action[] table.
*/
/*
** The state of the yy_action table under construction is an instance of
** the following structure
*/
typedef struct acttab acttab;
struct acttab {
int nAction; /* Number of used slots in aAction[] */
int nActionAlloc; /* Slots allocated for aAction[] */
struct {
int lookahead; /* Value of the lookahead token */
int action; /* Action to take on the given lookahead */
} *aAction, /* The yy_action[] table under construction */
*aLookahead; /* A single new transaction set */
int mnLookahead; /* Minimum aLookahead[].lookahead */
int mnAction; /* Action associated with mnLookahead */
int mxLookahead; /* Maximum aLookahead[].lookahead */
int nLookahead; /* Used slots in aLookahead[] */
int nLookaheadAlloc; /* Slots allocated in aLookahead[] */
};
/* Return the number of entries in the yy_action table */
#define acttab_size(X) ((X)->nAction)
/* The value for the N-th entry in yy_action */
#define acttab_yyaction(X,N) ((X)->aAction[N].action)
/* The value for the N-th entry in yy_lookahead */
#define acttab_yylookahead(X,N) ((X)->aAction[N].lookahead)
/* Free all memory associated with the given acttab */
/*
PRIVATE void acttab_free(acttab *p){
free( p->aAction );
free( p->aLookahead );
free( p );
}
*/
/* Allocate a new acttab structure */
PRIVATE acttab *acttab_alloc(void){
acttab *p = malloc( sizeof(*p) );
if( p==0 ){
fprintf(stderr,"Unable to allocate memory for a new acttab.");
exit(1);
}
memset(p, 0, sizeof(*p));
return p;
}
/* Add a new action to the current transaction set
*/
PRIVATE void acttab_action(acttab *p, int lookahead, int action){
if( p->nLookahead>=p->nLookaheadAlloc ){
p->nLookaheadAlloc += 25;
p->aLookahead = realloc( p->aLookahead,
sizeof(p->aLookahead[0])*p->nLookaheadAlloc );
if( p->aLookahead==0 ){
fprintf(stderr,"malloc failed\n");
exit(1);
}
}
if( p->nLookahead==0 ){
p->mxLookahead = lookahead;
p->mnLookahead = lookahead;
p->mnAction = action;
}else{
if( p->mxLookahead<lookahead ) p->mxLookahead = lookahead;
if( p->mnLookahead>lookahead ){
p->mnLookahead = lookahead;
p->mnAction = action;
}
}
p->aLookahead[p->nLookahead].lookahead = lookahead;
p->aLookahead[p->nLookahead].action = action;
p->nLookahead++;
}
/*
** Add the transaction set built up with prior calls to acttab_action()
** into the current action table. Then reset the transaction set back
** to an empty set in preparation for a new round of acttab_action() calls.
**
** Return the offset into the action table of the new transaction.
*/
PRIVATE int acttab_insert(acttab *p){
int i, j, k, n;
assert( p->nLookahead>0 );
/* Make sure we have enough space to hold the expanded action table
** in the worst case. The worst case occurs if the transaction set
** must be appended to the current action table
*/
n = p->mxLookahead + 1;
if( p->nAction + n >= p->nActionAlloc ){
int oldAlloc = p->nActionAlloc;
p->nActionAlloc = p->nAction + n + p->nActionAlloc + 20;
p->aAction = realloc( p->aAction,
sizeof(p->aAction[0])*p->nActionAlloc);
if( p->aAction==0 ){
fprintf(stderr,"malloc failed\n");
exit(1);
}
for(i=oldAlloc; i<p->nActionAlloc; i++){
p->aAction[i].lookahead = -1;
p->aAction[i].action = -1;
}
}
/* Scan the existing action table looking for an offset where we can
** insert the current transaction set. Fall out of the loop when that
** offset is found. In the worst case, we fall out of the loop when
** i reaches p->nAction, which means we append the new transaction set.
**
** i is the index in p->aAction[] where p->mnLookahead is inserted.
*/
for(i=0; i<p->nAction+p->mnLookahead; i++){
if( p->aAction[i].lookahead<0 ){
for(j=0; j<p->nLookahead; j++){
k = p->aLookahead[j].lookahead - p->mnLookahead + i;
if( k<0 ) break;
if( p->aAction[k].lookahead>=0 ) break;
}
if( j<p->nLookahead ) continue;
for(j=0; j<p->nAction; j++){
if( p->aAction[j].lookahead==j+p->mnLookahead-i ) break;
}
if( j==p->nAction ){
break; /* Fits in empty slots */
}
}else if( p->aAction[i].lookahead==p->mnLookahead ){
if( p->aAction[i].action!=p->mnAction ) continue;
for(j=0; j<p->nLookahead; j++){
k = p->aLookahead[j].lookahead - p->mnLookahead + i;
if( k<0 || k>=p->nAction ) break;
if( p->aLookahead[j].lookahead!=p->aAction[k].lookahead ) break;
if( p->aLookahead[j].action!=p->aAction[k].action ) break;
}
if( j<p->nLookahead ) continue;
n = 0;
for(j=0; j<p->nAction; j++){
if( p->aAction[j].lookahead<0 ) continue;
if( p->aAction[j].lookahead==j+p->mnLookahead-i ) n++;
}
if( n==p->nLookahead ){
break; /* Same as a prior transaction set */
}
}
}
/* Insert transaction set at index i. */
for(j=0; j<p->nLookahead; j++){
k = p->aLookahead[j].lookahead - p->mnLookahead + i;
p->aAction[k] = p->aLookahead[j];
if( k>=p->nAction ) p->nAction = k+1;
}
p->nLookahead = 0;
/* Return the offset that is added to the lookahead in order to get the
** index into yy_action of the action */
return i - p->mnLookahead;
}
/********************** From the file "assert.c" ****************************/
/*
** A more efficient way of handling assertions.
*/
void myassert(file,line)
char *file;
int line;
{
fprintf(stderr,"Assertion failed on line %d of file \"%s\"\n",line,file);
exit(1);
}
/********************** From the file "build.c" *****************************/
/*
** Routines to construction the finite state machine for the LEMON
** parser generator.
*/
/* Find a precedence symbol of every rule in the grammar.
**
** Those rules which have a precedence symbol coded in the input
** grammar using the "[symbol]" construct will already have the
** rp->precsym field filled. Other rules take as their precedence
** symbol the first RHS symbol with a defined precedence. If there
** are not RHS symbols with a defined precedence, the precedence
** symbol field is left blank.
*/
void FindRulePrecedences(xp)
struct lemon *xp;
{
struct rule *rp;
for(rp=xp->rule; rp; rp=rp->next){
if( rp->precsym==0 ){
int i;
for(i=0; i<rp->nrhs; i++){
if( rp->rhs[i]->prec>=0 ){
rp->precsym = rp->rhs[i];
break;
}
}
}
}
return;
}
/* Find all nonterminals which will generate the empty string.
** Then go back and compute the first sets of every nonterminal.
** The first set is the set of all terminal symbols which can begin
** a string generated by that nonterminal.
*/
void FindFirstSets(lemp)
struct lemon *lemp;
{
int i;
struct rule *rp;
int progress;
for(i=0; i<lemp->nsymbol; i++){
lemp->symbols[i]->lambda = Bo_FALSE;
}
for(i=lemp->nterminal; i<lemp->nsymbol; i++){
lemp->symbols[i]->firstset = SetNew();
}
/* First compute all lambdas */
do{
progress = 0;
for(rp=lemp->rule; rp; rp=rp->next){
if( rp->lhs->lambda ) continue;
for(i=0; i<rp->nrhs; i++){
if( rp->rhs[i]->lambda==Bo_FALSE ) break;
}
if( i==rp->nrhs ){
rp->lhs->lambda = Bo_TRUE;
progress = 1;
}
}
}while( progress );
/* Now compute all first sets */
do{
struct symbol *s1, *s2;
progress = 0;
for(rp=lemp->rule; rp; rp=rp->next){
s1 = rp->lhs;
for(i=0; i<rp->nrhs; i++){
s2 = rp->rhs[i];
if( s2->type==TERMINAL ){
progress += SetAdd(s1->firstset,s2->index);
break;
}else if( s1==s2 ){
if( s1->lambda==Bo_FALSE ) break;
}else{
progress += SetUnion(s1->firstset,s2->firstset);
if( s2->lambda==Bo_FALSE ) break;
}
}
}
}while( progress );
return;
}
/* Compute all LR(0) states for the grammar. Links
** are added to between some states so that the LR(1) follow sets
** can be computed later.
*/
PRIVATE struct state *getstate(/* struct lemon * */); /* forward reference */
void FindStates(lemp)
struct lemon *lemp;
{
struct symbol *sp;
struct rule *rp;
Configlist_init();
/* Find the start symbol */
if( lemp->start ){
sp = Symbol_find(lemp->start);
if( sp==0 ){
ErrorMsg(lemp->filename,0,
"The specified start symbol \"%s\" is not \
in a nonterminal of the grammar. \"%s\" will be used as the start \
symbol instead.",lemp->start,lemp->rule->lhs->name);
lemp->errorcnt++;
sp = lemp->rule->lhs;
}
}else{
sp = lemp->rule->lhs;
}
/* Make sure the start symbol doesn't occur on the right-hand side of
** any rule. Report an error if it does. (YACC would generate a new
** start symbol in this case.) */
for(rp=lemp->rule; rp; rp=rp->next){
int i;
for(i=0; i<rp->nrhs; i++){
if( rp->rhs[i]==sp ){
ErrorMsg(lemp->filename,0,
"The start symbol \"%s\" occurs on the \
right-hand side of a rule. This will result in a parser which \
does not work properly.",sp->name);
lemp->errorcnt++;
}
}
}
/* The basis configuration set for the first state
** is all rules which have the start symbol as their
** left-hand side */
for(rp=sp->rule; rp; rp=rp->nextlhs){
struct config *newcfp;
newcfp = Configlist_addbasis(rp,0);
SetAdd(newcfp->fws,0);
}
/* Compute the first state. All other states will be
** computed automatically during the computation of the first one.
** The returned pointer to the first state is not used. */
(void)getstate(lemp);
return;
}
/* Return a pointer to a state which is described by the configuration
** list which has been built from calls to Configlist_add.
*/
PRIVATE void buildshifts(/* struct lemon *, struct state * */); /* Forwd ref */
PRIVATE struct state *getstate(lemp)
struct lemon *lemp;
{
struct config *cfp, *bp;
struct state *stp;
/* Extract the sorted basis of the new state. The basis was constructed
** by prior calls to "Configlist_addbasis()". */
Configlist_sortbasis();
bp = Configlist_basis();
/* Get a state with the same basis */
stp = State_find(bp);
if( stp ){
/* A state with the same basis already exists! Copy all the follow-set
** propagation links from the state under construction into the
** preexisting state, then return a pointer to the preexisting state */
struct config *x, *y;
for(x=bp, y=stp->bp; x && y; x=x->bp, y=y->bp){
Plink_copy(&y->bplp,x->bplp);
Plink_delete(x->fplp);
x->fplp = x->bplp = 0;
}
cfp = Configlist_return();
Configlist_eat(cfp);
}else{
/* This really is a new state. Construct all the details */
Configlist_closure(lemp); /* Compute the configuration closure */
Configlist_sort(); /* Sort the configuration closure */
cfp = Configlist_return(); /* Get a pointer to the config list */
stp = State_new(); /* A new state structure */
MemoryCheck(stp);
stp->bp = bp; /* Remember the configuration basis */
stp->cfp = cfp; /* Remember the configuration closure */
stp->index = lemp->nstate++; /* Every state gets a sequence number */
stp->ap = 0; /* No actions, yet. */
State_insert(stp,stp->bp); /* Add to the state table */
buildshifts(lemp,stp); /* Recursively compute successor states */
}
return stp;
}
/* Construct all successor states to the given state. A "successor"
** state is any state which can be reached by a shift action.
*/
PRIVATE void buildshifts(lemp,stp)
struct lemon *lemp;
struct state *stp; /* The state from which successors are computed */
{
struct config *cfp; /* For looping thru the config closure of "stp" */
struct config *bcfp; /* For the inner loop on config closure of "stp" */
struct config *new; /* */
struct symbol *sp; /* Symbol following the dot in configuration "cfp" */
struct symbol *bsp; /* Symbol following the dot in configuration "bcfp" */
struct state *newstp; /* A pointer to a successor state */
/* Each configuration becomes complete after it contibutes to a successor
** state. Initially, all configurations are incomplete */
for(cfp=stp->cfp; cfp; cfp=cfp->next) cfp->status = INCOMPLETE;
/* Loop through all configurations of the state "stp" */
for(cfp=stp->cfp; cfp; cfp=cfp->next){
if( cfp->status==COMPLETE ) continue; /* Already used by inner loop */
if( cfp->dot>=cfp->rp->nrhs ) continue; /* Can't shift this config */
Configlist_reset(); /* Reset the new config set */
sp = cfp->rp->rhs[cfp->dot]; /* Symbol after the dot */
/* For every configuration in the state "stp" which has the symbol "sp"
** following its dot, add the same configuration to the basis set under
** construction but with the dot shifted one symbol to the right. */
for(bcfp=cfp; bcfp; bcfp=bcfp->next){
if( bcfp->status==COMPLETE ) continue; /* Already used */
if( bcfp->dot>=bcfp->rp->nrhs ) continue; /* Can't shift this one */
bsp = bcfp->rp->rhs[bcfp->dot]; /* Get symbol after dot */
if( bsp!=sp ) continue; /* Must be same as for "cfp" */
bcfp->status = COMPLETE; /* Mark this config as used */
new = Configlist_addbasis(bcfp->rp,bcfp->dot+1);
Plink_add(&new->bplp,bcfp);
}
/* Get a pointer to the state described by the basis configuration set
** constructed in the preceding loop */
newstp = getstate(lemp);
/* The state "newstp" is reached from the state "stp" by a shift action
** on the symbol "sp" */
Action_add(&stp->ap,SHIFT,sp,newstp);
}
}
/*
** Construct the propagation links
*/
void FindLinks(lemp)
struct lemon *lemp;
{
int i;
struct config *cfp, *other;
struct state *stp;
struct plink *plp;
/* Housekeeping detail:
** Add to every propagate link a pointer back to the state to
** which the link is attached. */
for(i=0; i<lemp->nstate; i++){
stp = lemp->sorted[i];
for(cfp=stp->cfp; cfp; cfp=cfp->next){
cfp->stp = stp;
}
}
/* Convert all backlinks into forward links. Only the forward
** links are used in the follow-set computation. */
for(i=0; i<lemp->nstate; i++){
stp = lemp->sorted[i];
for(cfp=stp->cfp; cfp; cfp=cfp->next){
for(plp=cfp->bplp; plp; plp=plp->next){
other = plp->cfp;
Plink_add(&other->fplp,cfp);
}
}
}
}
/* Compute all followsets.
**
** A followset is the set of all symbols which can come immediately
** after a configuration.
*/
void FindFollowSets(lemp)
struct lemon *lemp;
{
int i;
struct config *cfp;
struct state *stp;
struct plink *plp;
int progress;
int change;
for(i=0; i<lemp->nstate; i++){
stp = lemp->sorted[i];
for(cfp=stp->cfp; cfp; cfp=cfp->next){
cfp->status = INCOMPLETE;
}
}
do{
progress = 0;
for(i=0; i<lemp->nstate; i++){
stp = lemp->sorted[i];
for(cfp=stp->cfp; cfp; cfp=cfp->next){
if( cfp->status==COMPLETE ) continue;
for(plp=cfp->fplp; plp; plp=plp->next){
change = SetUnion(plp->cfp->fws,cfp->fws);
if( change ){
plp->cfp->status = INCOMPLETE;
progress = 1;
}
}
cfp->status = COMPLETE;
}
}
}while( progress );
}
static int resolve_conflict();
/* Compute the reduce actions, and resolve conflicts.
*/
void FindActions(lemp)
struct lemon *lemp;
{
int i,j;
struct config *cfp;
struct symbol *sp;
struct rule *rp;
/* Add all of the reduce actions
** A reduce action is added for each element of the followset of
** a configuration which has its dot at the extreme right.
*/
for(i=0; i<lemp->nstate; i++){ /* Loop over all states */
struct state *stp;
stp = lemp->sorted[i];
for(cfp=stp->cfp; cfp; cfp=cfp->next){ /* Loop over all configurations */
if( cfp->rp->nrhs==cfp->dot ){ /* Is dot at extreme right? */
for(j=0; j<lemp->nterminal; j++){
if( SetFind(cfp->fws,j) ){
/* Add a reduce action to the state "stp" which will reduce by the
** rule "cfp->rp" if the lookahead symbol is "lemp->symbols[j]" */
Action_add(&stp->ap,REDUCE,lemp->symbols[j],cfp->rp);
}
}
}
}
}
/* Add the accepting token */
if( lemp->start ){
sp = Symbol_find(lemp->start);
if( sp==0 ) sp = lemp->rule->lhs;
}else{
sp = lemp->rule->lhs;
}
/* Add to the first state (which is always the starting state of the
** finite state machine) an action to ACCEPT if the lookahead is the
** start nonterminal. */
if (lemp->nstate) { /*(should always be true)*/
struct state *stp;
stp = lemp->sorted[0];
Action_add(&stp->ap,ACCEPT,sp,0);
}
/* Resolve conflicts */
for(i=0; i<lemp->nstate; i++){
struct action *ap, *nap;
struct state *stp;
stp = lemp->sorted[i];
assert( stp->ap );
stp->ap = Action_sort(stp->ap);
for(ap=stp->ap; ap && ap->next; ap=ap->next){
for(nap=ap->next; nap && nap->sp==ap->sp; nap=nap->next){
/* The two actions "ap" and "nap" have the same lookahead.
** Figure out which one should be used */
lemp->nconflict += resolve_conflict(ap,nap,lemp->errsym);
}
}
}
/* Report an error for each rule that can never be reduced. */
for(rp=lemp->rule; rp; rp=rp->next) rp->canReduce = Bo_FALSE;
for(i=0; i<lemp->nstate; i++){
struct action *ap;
for(ap=lemp->sorted[i]->ap; ap; ap=ap->next){
if( ap->type==REDUCE ) ap->x.rp->canReduce = Bo_TRUE;
}
}
for(rp=lemp->rule; rp; rp=rp->next){
if( rp->canReduce ) continue;
ErrorMsg(lemp->filename,rp->ruleline,"This rule can not be reduced.\n");
lemp->errorcnt++;
}
}
/* Resolve a conflict between the two given actions. If the
** conflict can't be resolve, return non-zero.
**
** NO LONGER TRUE:
** To resolve a conflict, first look to see if either action
** is on an error rule. In that case, take the action which
** is not associated with the error rule. If neither or both
** actions are associated with an error rule, then try to
** use precedence to resolve the conflict.
**
** If either action is a SHIFT, then it must be apx. This
** function won't work if apx->type==REDUCE and apy->type==SHIFT.
*/
static int resolve_conflict(apx,apy,errsym)
struct action *apx;
struct action *apy;
struct symbol *errsym; /* The error symbol (if defined. NULL otherwise) */
{
struct symbol *spx, *spy;
int errcnt = 0;
UNUSED(errsym);
assert( apx->sp==apy->sp ); /* Otherwise there would be no conflict */
if( apx->type==SHIFT && apy->type==REDUCE ){
spx = apx->sp;
spy = apy->x.rp->precsym;
if( spy==0 || spx->prec<0 || spy->prec<0 ){
/* Not enough precedence information. */
apy->type = CONFLICT;
errcnt++;
}else if( spx->prec>spy->prec ){ /* Lower precedence wins */
apy->type = RD_RESOLVED;
}else if( spx->prec<spy->prec ){
apx->type = SH_RESOLVED;
}else if( spx->prec==spy->prec && spx->assoc==RIGHT ){ /* Use operator */
apy->type = RD_RESOLVED; /* associativity */
}else if( spx->prec==spy->prec && spx->assoc==LEFT ){ /* to break tie */
apx->type = SH_RESOLVED;
}else{
assert( spx->prec==spy->prec && spx->assoc==NONE );
apy->type = CONFLICT;
errcnt++;
}
}else if( apx->type==REDUCE && apy->type==REDUCE ){
spx = apx->x.rp->precsym;
spy = apy->x.rp->precsym;
if(