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5179 lines (4875 loc) · 154 KB
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/*
** 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 <assert.h>
#define ISSPACE(X) isspace((unsigned char)(X))
#define ISDIGIT(X) isdigit((unsigned char)(X))
#define ISALNUM(X) isalnum((unsigned char)(X))
#define ISALPHA(X) isalpha((unsigned char)(X))
#define ISUPPER(X) isupper((unsigned char)(X))
#define ISLOWER(X) islower((unsigned char)(X))
#ifndef __WIN32__
# if defined(_WIN32) || defined(WIN32)
# define __WIN32__
# endif
#endif
#ifdef __WIN32__
#ifdef __cplusplus
extern "C" {
#endif
extern int access(const char *path, int mode);
#ifdef __cplusplus
}
#endif
#else
#include <unistd.h>
#endif
/* #define PRIVATE static */
#define PRIVATE
#ifdef TEST
#define MAXRHS 5 /* Set low to exercise exception code */
#else
#define MAXRHS 1000
#endif
static int showPrecedenceConflict = 0;
static char *msort(char*,char**,int(*)(const char*,const char*));
/*
** Compilers are getting increasingly pedantic about type conversions
** as C evolves ever closer to Ada.... To work around the latest problems
** we have to define the following variant of strlen().
*/
#define lemonStrlen(X) ((int)strlen(X))
/*
** Compilers are starting to complain about the use of sprintf() and strcpy(),
** saying they are unsafe. So we define our own versions of those routines too.
**
** There are three routines here: lemon_sprintf(), lemon_vsprintf(), and
** lemon_addtext(). The first two are replacements for sprintf() and vsprintf().
** The third is a helper routine for vsnprintf() that adds texts to the end of a
** buffer, making sure the buffer is always zero-terminated.
**
** The string formatter is a minimal subset of stdlib sprintf() supporting only
** a few simply conversions:
**
** %d
** %s
** %.*s
**
*/
static void lemon_addtext(
char *zBuf, /* The buffer to which text is added */
int *pnUsed, /* Slots of the buffer used so far */
const char *zIn, /* Text to add */
int nIn, /* Bytes of text to add. -1 to use strlen() */
int iWidth /* Field width. Negative to left justify */
){
if( nIn<0 ) for(nIn=0; zIn[nIn]; nIn++){}
while( iWidth>nIn ){ zBuf[(*pnUsed)++] = ' '; iWidth--; }
if( nIn==0 ) return;
memcpy(&zBuf[*pnUsed], zIn, nIn);
*pnUsed += nIn;
while( (-iWidth)>nIn ){ zBuf[(*pnUsed)++] = ' '; iWidth++; }
zBuf[*pnUsed] = 0;
}
static int lemon_vsprintf(char *str, const char *zFormat, va_list ap){
int i, j, k, c;
int nUsed = 0;
const char *z;
char zTemp[50];
str[0] = 0;
for(i=j=0; (c = zFormat[i])!=0; i++){
if( c=='%' ){
int iWidth = 0;
lemon_addtext(str, &nUsed, &zFormat[j], i-j, 0);
c = zFormat[++i];
if( ISDIGIT(c) || (c=='-' && ISDIGIT(zFormat[i+1])) ){
if( c=='-' ) i++;
while( ISDIGIT(zFormat[i]) ) iWidth = iWidth*10 + zFormat[i++] - '0';
if( c=='-' ) iWidth = -iWidth;
c = zFormat[i];
}
if( c=='d' ){
int v = va_arg(ap, int);
if( v<0 ){
lemon_addtext(str, &nUsed, "-", 1, iWidth);
v = -v;
}else if( v==0 ){
lemon_addtext(str, &nUsed, "0", 1, iWidth);
}
k = 0;
while( v>0 ){
k++;
zTemp[sizeof(zTemp)-k] = (v%10) + '0';
v /= 10;
}
lemon_addtext(str, &nUsed, &zTemp[sizeof(zTemp)-k], k, iWidth);
}else if( c=='s' ){
z = va_arg(ap, const char*);
lemon_addtext(str, &nUsed, z, -1, iWidth);
}else if( c=='.' && memcmp(&zFormat[i], ".*s", 3)==0 ){
i += 2;
k = va_arg(ap, int);
z = va_arg(ap, const char*);
lemon_addtext(str, &nUsed, z, k, iWidth);
}else if( c=='%' ){
lemon_addtext(str, &nUsed, "%", 1, 0);
}else{
fprintf(stderr, "illegal format\n");
exit(1);
}
j = i+1;
}
}
lemon_addtext(str, &nUsed, &zFormat[j], i-j, 0);
return nUsed;
}
static int lemon_sprintf(char *str, const char *format, ...){
va_list ap;
int rc;
va_start(ap, format);
rc = lemon_vsprintf(str, format, ap);
va_end(ap);
return rc;
}
static void lemon_strcpy(char *dest, const char *src){
while( (*(dest++) = *(src++))!=0 ){}
}
static void lemon_strcat(char *dest, const char *src){
while( *dest ) dest++;
lemon_strcpy(dest, src);
}
/* a few forward declarations... */
struct rule;
struct lemon;
struct action;
static struct action *Action_new(void);
static struct action *Action_sort(struct action *);
/********** 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(struct lemon *);
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" ******************************************/
enum option_type { OPT_FLAG=1, OPT_INT, OPT_DBL, OPT_STR,
OPT_FFLAG, OPT_FINT, OPT_FDBL, OPT_FSTR};
struct s_options {
enum option_type type;
const char *label;
char *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 *, int);
void ReportHeader(struct lemon *);
void CompressTables(struct lemon *);
void ResortStates(struct lemon *);
/********** From the file "set.h" ****************************************/
void SetSize(int); /* 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 *,char *); /* 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 {LEMON_FALSE=0, LEMON_TRUE} Boolean;
/* Symbols (terminals and nonterminals) of the grammar are stored
** in the following: */
enum symbol_type {
TERMINAL,
NONTERMINAL,
MULTITERMINAL
};
enum e_assoc {
LEFT,
RIGHT,
NONE,
UNK
};
struct symbol {
const char *name; /* Name of the symbol */
int index; /* Index number for this symbol */
enum symbol_type 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 assoc; /* Associativity if precedence is defined */
char *firstset; /* First-set for all rules of this symbol */
Boolean lambda; /* True if NT and can generate an empty string */
int useCnt; /* Number of times used */
char *destructor; /* Code which executes whenever this symbol is
** popped from the stack during error processing */
int destLineno; /* Line number for start of destructor */
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 */
/* The following fields are used by MULTITERMINALs only */
int nsubsym; /* Number of constituent symbols in the MULTI */
struct symbol **subsym; /* Array of constituent symbols */
};
/* Each production rule in the grammar is stored in the following
** structure. */
struct rule {
struct symbol *lhs; /* Left-hand side of the rule */
const char *lhsalias; /* Alias for the LHS (NULL if none) */
int lhsStart; /* True if left-hand side is the start symbol */
int ruleline; /* Line number for the rule */
int nrhs; /* Number of RHS symbols */
struct symbol **rhs; /* The RHS symbols */
const char **rhsalias; /* An alias for each RHS symbol (NULL if none) */
int line; /* Line number at which code begins */
const 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: */
enum cfgstatus {
COMPLETE,
INCOMPLETE
};
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 cfgstatus status; /* used during followset and shift computations */
struct config *next; /* Next configuration in the state */
struct config *bp; /* The next basis configuration */
};
enum e_action {
SHIFT,
ACCEPT,
REDUCE,
ERROR,
SSCONFLICT, /* A shift/shift conflict */
SRCONFLICT, /* Was a reduce, but part of a conflict */
RRCONFLICT, /* 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 */
SHIFTREDUCE /* Shift first, then reduce */
};
/* Every shift or reduce operation is stored as one of the following */
struct action {
struct symbol *sp; /* The look-ahead symbol */
enum e_action 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 statenum; /* Sequential 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 iDfltReduce; /* Default action is to REDUCE by this rule */
struct rule *pDfltReduce;/* The default REDUCE rule. */
int autoReduce; /* True if this is an auto-reduce state */
};
#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 nxstate; /* nstate with tail degenerate states removed */
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 */
struct symbol *wildcard; /* Token that matches anything */
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 */
char *error; /* Code to execute when an error is seen */
char *overflow; /* Code to execute on a stack overflow */
char *failure; /* Code to execute on parser failure */
char *accept; /* Code to execute when the parser excepts */
char *extracode; /* Code appended to the generated file */
char *tokendest; /* Code to execute to destroy token data */
char *vardest; /* Code for the default non-terminal destructor */
char *filename; /* Name of the input 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 nactiontab; /* Number of entries in the yy_action[] table */
int tablesize; /* Total table size of all tables in bytes */
int basisflag; /* Print only basis configurations */
int has_fallback; /* True if any %fallback is seen in the grammar */
int nolinenosflag; /* True if #line statements should not be printed */
char *argv0; /* Name of the program */
};
#define MemoryCheck(X) if((X)==0){ \
extern void memory_error(); \
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 */
const char *Strsafe(const char *);
void Strsafe_init(void);
int Strsafe_insert(const char *);
const char *Strsafe_find(const char *);
/* Routines for handling symbols of the grammar */
struct symbol *Symbol_new(const char *);
int Symbolcmpp(const void *, const void *);
void Symbol_init(void);
int Symbol_insert(struct symbol *, const char *);
struct symbol *Symbol_find(const char *);
struct symbol *Symbol_Nth(int);
int Symbol_count(void);
struct symbol **Symbol_arrayof(void);
/* Routines to manage the state table */
int Configcmp(const char *, const char *);
struct state *State_new(void);
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 */
static struct action *Action_new(void){
static struct action *freelist = 0;
struct action *newaction;
if( freelist==0 ){
int i;
int amt = 100;
freelist = (struct action *)calloc(amt, sizeof(struct action));
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;
}
newaction = freelist;
freelist = freelist->next;
return newaction;
}
/* Compare two actions for sorting purposes. Return negative, zero, or
** positive if the first action is less than, equal to, or greater than
** the first
*/
static int actioncmp(
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 && (ap1->type==REDUCE || ap1->type==SHIFTREDUCE) ){
rc = ap1->x.rp->index - ap2->x.rp->index;
}
if( rc==0 ){
rc = (int) (ap2 - ap1);
}
return rc;
}
/* Sort parser actions */
static struct action *Action_sort(
struct action *ap
){
ap = (struct action *)msort((char *)ap,(char **)&ap->next,
(int(*)(const char*,const char*))actioncmp);
return ap;
}
void Action_add(
struct action **app,
enum e_action type,
struct symbol *sp,
char *arg
){
struct action *newaction;
newaction = Action_new();
newaction->next = *app;
*app = newaction;
newaction->type = type;
newaction->sp = sp;
if( type==SHIFT ){
newaction->x.stp = (struct state *)arg;
}else{
newaction->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.
**
** The yy_action table maps the pair (state_number, lookahead) into an
** action_number. The table is an array of integers pairs. The state_number
** determines an initial offset into the yy_action array. The lookahead
** value is then added to this initial offset to get an index X into the
** yy_action array. If the aAction[X].lookahead equals the value of the
** of the lookahead input, then the value of the action_number output is
** aAction[X].action. If the lookaheads do not match then the
** default action for the state_number is returned.
**
** All actions associated with a single state_number are first entered
** into aLookahead[] using multiple calls to acttab_action(). Then the
** actions for that single state_number are placed into the aAction[]
** array with a single call to acttab_insert(). The acttab_insert() call
** also resets the aLookahead[] array in preparation for the next
** state number.
*/
struct lookahead_action {
int lookahead; /* Value of the lookahead token */
int action; /* Action to take on the given lookahead */
};
typedef struct acttab acttab;
struct acttab {
int nAction; /* Number of used slots in aAction[] */
int nActionAlloc; /* Slots allocated for aAction[] */
struct lookahead_action
*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 */
void acttab_free(acttab *p){
free( p->aAction );
free( p->aLookahead );
free( p );
}
/* Allocate a new acttab structure */
acttab *acttab_alloc(void){
acttab *p = (acttab *) calloc( 1, 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.
**
** This routine is called once for each lookahead for a particular
** state.
*/
void acttab_action(acttab *p, int lookahead, int action){
if( p->nLookahead>=p->nLookaheadAlloc ){
p->nLookaheadAlloc += 25;
p->aLookahead = (struct lookahead_action *) 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.
*/
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 = (struct lookahead_action *) 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 that is a
** duplicate of the current transaction set. Fall out of the loop
** if and when the duplicate is found.
**
** i is the index in p->aAction[] where p->mnLookahead is inserted.
*/
for(i=p->nAction-1; i>=0; i--){
if( p->aAction[i].lookahead==p->mnLookahead ){
/* All lookaheads and actions in the aLookahead[] transaction
** must match against the candidate aAction[i] entry. */
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;
/* No possible lookahead value that is not in the aLookahead[]
** transaction is allowed to match aAction[i] */
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; /* An exact match is found at offset i */
}
}
}
/* If no existing offsets exactly match the current transaction, find an
** an empty offset in the aAction[] table in which we can add the
** aLookahead[] transaction.
*/
if( i<0 ){
/* Look for holes in the aAction[] table that fit the current
** aLookahead[] transaction. Leave i set to the offset of the hole.
** If no holes are found, i is left at p->nAction, which means the
** transaction will be appended. */
for(i=0; i<p->nActionAlloc - p->mxLookahead; 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 */
}
}
}
}
/* 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 "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(struct lemon *xp)
{
struct rule *rp;
for(rp=xp->rule; rp; rp=rp->next){
if( rp->precsym==0 ){
int i, j;
for(i=0; i<rp->nrhs && rp->precsym==0; i++){
struct symbol *sp = rp->rhs[i];
if( sp->type==MULTITERMINAL ){
for(j=0; j<sp->nsubsym; j++){
if( sp->subsym[j]->prec>=0 ){
rp->precsym = sp->subsym[j];
break;
}
}
}else if( sp->prec>=0 ){
rp->precsym = rp->rhs[i];
}
}
}
}
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(struct lemon *lemp)
{
int i, j;
struct rule *rp;
int progress;
for(i=0; i<lemp->nsymbol; i++){
lemp->symbols[i]->lambda = LEMON_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++){
struct symbol *sp = rp->rhs[i];
assert( sp->type==NONTERMINAL || sp->lambda==LEMON_FALSE );
if( sp->lambda==LEMON_FALSE ) break;
}
if( i==rp->nrhs ){
rp->lhs->lambda = LEMON_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( s2->type==MULTITERMINAL ){
for(j=0; j<s2->nsubsym; j++){
progress += SetAdd(s1->firstset,s2->subsym[j]->index);
}
break;
}else if( s1==s2 ){
if( s1->lambda==LEMON_FALSE ) break;
}else{
progress += SetUnion(s1->firstset,s2->firstset);
if( s2->lambda==LEMON_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(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 ){ /* FIX ME: Deal with multiterminals */
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;
rp->lhsStart = 1;
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(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->statenum = 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;
}
/*
** Return true if two symbols are the same.
*/
int same_symbol(struct symbol *a, struct symbol *b)
{
int i;
if( a==b ) return 1;
if( a->type!=MULTITERMINAL ) return 0;
if( b->type!=MULTITERMINAL ) return 0;
if( a->nsubsym!=b->nsubsym ) return 0;
for(i=0; i<a->nsubsym; i++){
if( a->subsym[i]!=b->subsym[i] ) return 0;
}
return 1;
}
/* 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(struct lemon *lemp, struct state *stp)
{
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 *newcfg; /* */
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( !same_symbol(bsp,sp) ) continue; /* Must be same as for "cfp" */
bcfp->status = COMPLETE; /* Mark this config as used */
newcfg = Configlist_addbasis(bcfp->rp,bcfp->dot+1);
Plink_add(&newcfg->bplp,bcfp);
}
/* Get a pointer to the state described by the basis configuration set
** constructed in the preceding loop */
newstp = getstate(lemp);