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parser.c
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parser.c
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/*
System: Structured text retrieval tool sgrep.
Module: parser.c
Author: Pekka Kilpeläinen & Jani Jaakkola
Description: Parses expression string ( which has been gathered in
main.c and preprocessed in preprocess.c )
Returns operator tree.
Used through fuction parse_tree()
Version history: Original version February 1995 by JJ & PK
Copyright: University of Helsinki, Dept. of Computer Science
*/
#include <ctype.h> /* FIXME: get rid of ctype.h */
#include <string.h>
#define SGREP_LIBRARY
#include "sgrep.h"
/* Maximum length of one phrase. */
#define MAX_PHRASE_LENGTH 512
/* Maximum length of a reserved word. Could also be smaller */
#define MAX_R_WORD 20
#define ELLENGTH 79
#define SHOWR 5
/*
* Tokens of sgrep query language
*/
enum Token {
/* Tokens for reserved words */
W_IN,W_NOT,W_CONTAINING,W_OR,
W_ORDERED,W_L_ORDERED,W_R_ORDERED,W_LR_ORDERED,
W_EXTRACTING,
W_QUOTE,W_L_QUOTE,W_R_QUOTE,W_LR_QUOTE,
W_EQUAL, /* PK Febr 12 '96 */
W_PARENTING,W_CHILDRENING,
W_NEAR, W_NEAR_BEFORE,
W_OUTER,W_INNER,W_CONCAT,
/* number functions */
W_JOIN, W_FIRST, W_LAST,
W_FIRST_BYTES,W_LAST_BYTES,
/* FIXME: what to do with "chars" */
W_CHARS,
/* The automagical phrases */
W_START,W_END,
/* Phrase types */
W_PROLOG,
W_ELEMENTS,
W_FILE,
W_STRING, W_REGEX,
W_DOCTYPE, W_DOCTYPE_PID, W_DOCTYPE_SID,
W_PI, W_ATTRIBUTE, W_ATTVALUE,
W_STAG, W_ETAG, W_COMMENT, W_COMMENT_WORD,
W_WORD, W_CDATA,
W_ENTITY, W_ENTITY_DECLARATION, W_ENTITY_LITERAL,
W_ENTITY_PID, W_ENTITY_SID, W_ENTITY_NDATA,
W_RAW,
R_WORDS,
/* And the rest */
W_LPAREN,W_RPAREN,W_LBRACK,W_RBRACK,W_COMMA,W_PHRASE,W_NUMBER,
/* End of file */
W_EOF,
/* In sgrep, parse error while scanning is just a kind of token */
W_PARSE_ERROR,
W_END_TOKENS
};
enum ScannerState {
SCANNER_START,
SCANNER_STRING,
SCANNER_NAME,
SCANNER_NUMBER,
SCANNER_COMMENT,
SCANNER_LINE_START_COMMENT,
SCANNER_LINE_NUMBER_COMMENT,
SCANNER_FILE_NAME_COMMENT_START,
SCANNER_FILE_NAME_COMMENT
};
/*
* Parser object
*/
typedef struct {
SgrepData *sgrep;
/* The command string and a index to it */
const char *expr_str;
int expr_ind;
/* Current character, token and string of current string token */
int ch;
enum Token token;
SgrepString *unexpanded_string_token;
SgrepString *string_token;
/* This points to first phrase in the phrase list */
struct PHRASE_NODE *first_phrase;
/* for telling where errors occurred */
int line,column;
SgrepString *file;
int errline,errcol,errind;
/* Scanners state */
enum ScannerState scanner_state;
/* Needed for freeing data after parse error */
int nodes;
ParseTreeNode *node_array[5000];
} Parser;
void real_parse_error(Parser *parser,char *);
int get_next_char(Parser *parser);
enum Token next_token(Parser *parser);
ParseTreeNode *create_tree_node(Parser *parser,enum Oper oper);
ParseTreeNode *parse_reg_expr(Parser *parser);
ParseTreeNode *parse_basic_expr(Parser *parser);
ParseTreeNode *parse_oper_expr(Parser *parser,ParseTreeNode *);
ParseTreeNode *parse_phrase(Parser *,const char *);
ParseTreeNode *parse_cons_list(Parser *parser);
ParseTreeNode *new_string_phrase(Parser *, SgrepString *,
const char *);
#ifdef DEBUG
void print_tree(ParseTreeNode *);
#endif
#define parse_error(E) \
do { real_parse_error(parser,(E));return NULL; } while (0)
#define token (parser->token)
#define NEXT_TOKEN \
do { token=next_token(parser); if (token==W_PARSE_ERROR) return NULL; } while (0);
/*
* When looking for reserved words they are matched to these strings
*/
struct {
const char *word;
enum Token t;
} reserved_words[]=
{
{"in",W_IN},
{"not",W_NOT},
{"containing",W_CONTAINING},
{"or",W_OR},
{"..",W_ORDERED},
{"_.",W_L_ORDERED},
{"._",W_R_ORDERED},
{"__",W_LR_ORDERED},
{"extracting", W_EXTRACTING},
{"quote",W_QUOTE},
{"_quote",W_L_QUOTE},
{"quote_",W_R_QUOTE},
{"_quote_",W_LR_QUOTE },
{"equal",W_EQUAL}, /* PK Febr 12 '96 */
{"parenting",W_PARENTING},
{"childrening",W_CHILDRENING},
{"near",W_NEAR},
{"near_before",W_NEAR_BEFORE},
{"outer",W_OUTER},
{"inner",W_INNER},
{"concat",W_CONCAT},
/* Constant lists */
{"chars",W_CHARS},
/* Number functions */
{"first",W_FIRST},
{"last",W_LAST},
{"first_bytes",W_FIRST_BYTES},
{"last_bytes",W_LAST_BYTES},
{"join",W_JOIN},
/* Automagical phrases */
{"start",W_START},
{"end",W_END},
/* Different phrases */
{"file",W_FILE},
{"string", W_STRING},
{"regex",W_REGEX},
{"pi", W_PI},
{"attribute", W_ATTRIBUTE},
{"attvalue",W_ATTVALUE},
{"stag", W_STAG},
{"etag", W_ETAG},
{"comments", W_COMMENT},
{"elements", W_ELEMENTS},
{"comment_word",W_COMMENT_WORD},
{"word", W_WORD},
{"cdata",W_CDATA},
{"entity",W_ENTITY},
/* Stuff from DTD */
{"prologs", W_PROLOG},
{"doctype", W_DOCTYPE},
{"doctype_pid", W_DOCTYPE_PID},
{"doctype_sid",W_DOCTYPE_SID},
{"entity_declaration",W_ENTITY_DECLARATION },
{"entity_literal",W_ENTITY_LITERAL },
{"entity_pid",W_ENTITY_PID },
{"entity_sid",W_ENTITY_SID },
{"entity_ndata",W_ENTITY_NDATA },
/* And the raw phrase */
{"raw", W_RAW },
{NULL,W_END_TOKENS}
};
/*
* Gives user readable operation name from given opernum
*/
const char *give_oper_name(int oper)
{
switch (oper) {
case IN: return "in";break;
case NOT_IN: return "not in";break;
case CONTAINING: return "containing";break;
case NOT_CONTAINING: return "not containing";break;
case EQUAL: return "equal";break; /* PK Febr'95 */
case NOT_EQUAL: return "not equal";break; /* PK Febr'95 */
case OR: return "or";break;
case ORDERED: return "..";break;
case L_ORDERED: return "_.";break;
case R_ORDERED: return "._";break;
case LR_ORDERED: return "__";break;
case EXTRACTING: return "extracting";break;
case OUTER: return "outer";break;
case INNER: return "inner";break;
case CONCAT: return "concat";break;
case JOIN: return "join";break;
case PHRASE: return "phrase";break;
case INVALID: return "invalid";break;
default: return "unknown";break;
}
}
/*
* Gets next character from input expression. Counts also lines and columns
* return character must be unsigned to keep sgrep is 8-bit clean
*/
int get_next_char(Parser *parser)
{
switch (parser->expr_str[parser->expr_ind]) {
case '\n':
parser->column=-1;
parser->line++;
break;
}
parser->column++;
return parser->ch=((unsigned char *)parser->expr_str)[parser->expr_ind++];
}
/*
* Scans next token from input string. If token was a phrase sets **phrase
*/
enum Token next_token(Parser *parser)
{
char str[MAX_PHRASE_LENGTH+1];
int i=0,j=0;
int start;
int ch;
SgrepString **phrase;
SGREPDATA(parser);
/* if we already have next character in ch then ch!=-1. Otherwise we have to
get one */
ch=parser->ch;
phrase=&parser->string_token;
if (ch==-1) ch=get_next_char(parser);
/* These show the place where possible error started */
parser->errline=parser->line;
parser->errcol=parser->column;
parser->errind=parser->expr_ind;
/* Finite automaton for recognizing next word */
do {
switch (parser->scanner_state) {
/* This is the start state */
case SCANNER_START:
/* skip the whitespace */
while (isspace(ch)) ch=get_next_char(parser);
/* These show the place where possible error started */
parser->errline=parser->line;
parser->errcol=parser->column;
parser->errind=parser->expr_ind;
switch(ch) {
case 0:
return W_EOF;
case '(':
parser->ch=-1;
return W_LPAREN;
case ')':
parser->ch=-1;
return W_RPAREN;
case '[':
parser->ch=-1;
return W_LBRACK;
case ']':
parser->ch=-1;
return W_RBRACK;
case ',':
parser->ch=-1;
return W_COMMA;
case '\"':
i=0;
parser->scanner_state=SCANNER_STRING;
break;
case '#':
parser->scanner_state=SCANNER_COMMENT;
break;
}
if ( isalpha(ch) || ch=='.' || ch=='_' )
{
i=1;
str[0]=tolower(ch);
parser->scanner_state=SCANNER_NAME;
start=parser->column;
}
if (ch>='0' && ch<='9')
{
i=1;
str[0]=ch;
start=parser->column;
parser->scanner_state=SCANNER_NUMBER;
}
if ( parser->scanner_state==SCANNER_START )
{
#ifdef DEBUG
fprintf(stderr,"Character %c ascii(%d)\n",ch,ch);
#endif
real_parse_error(parser,"Invalid character");
return W_PARSE_ERROR;
}
break;
/* This state reads a phrase string */
case SCANNER_STRING:
if (ch==0 || ch=='\n')
{
real_parse_error(parser,"Unterminated phrase string");
return W_PARSE_ERROR;
}
if ( ch<' ' ) {
real_parse_error(parser,"Unprintable character in phrase");
return W_PARSE_ERROR;
}
if (ch=='\"' && (i==0 || str[i-1]!='\\'))
{
str[i]=0;
*phrase=expand_backslashes(sgrep,str);
if (!(*phrase) || string_len(*phrase)==0) {
real_parse_error(parser,"Empty phrase");
return W_PARSE_ERROR;
}
parser->scanner_state=SCANNER_START;
parser->ch=-1;
return W_PHRASE;
}
if ( i==MAX_PHRASE_LENGTH )
{
sgrep_error(sgrep,"%s ( > %d ) %s %d\n%s\n%s\n",
"Phrase length exceeds",MAX_PHRASE_LENGTH,"on line",parser->line,
"Either you have forgotten the quote at the end of phrase or",
"you have to recompile with greater MAX_PHRASE_LENGTH.");
real_parse_error(parser,"");
return W_PARSE_ERROR;
}
if ( parser->scanner_state==SCANNER_STRING ) str[i++]=ch;
break;
/* This state reads a reserved word (operator) */
case SCANNER_NAME:
if ( ch==0 || ( !isalpha(ch) && ch!='.' && ch!='_' ) )
{
parser->scanner_state=SCANNER_START;
str[i]=0;
for(j=0;reserved_words[j].word;j++)
if (strcmp(reserved_words[j].word,str)==0)
return reserved_words[j].t;
real_parse_error(parser,"Unknown word");
return W_PARSE_ERROR;
}
if (i==MAX_R_WORD)
{
real_parse_error(parser,"Unknown word");
return W_PARSE_ERROR;
}
str[i++]=tolower(ch);
break;
/* This state skips comments */
case SCANNER_LINE_START_COMMENT:
if (parser->column<=6 &&
("#line ")[parser->column-1]==ch) {
break;
} else if (parser->column==7 && ch>='0' && ch<='9') {
parser->line=ch-'0'-1;
parser->scanner_state=SCANNER_LINE_NUMBER_COMMENT;
} else {
parser->scanner_state=SCANNER_COMMENT;
}
/* Fall through */
case SCANNER_COMMENT:
if (ch==0) {
parser->scanner_state=SCANNER_START;
return W_EOF;
} else if (ch=='\n') {
parser->scanner_state=SCANNER_START;
} else if (ch=='l' && parser->column==2) {
parser->scanner_state=SCANNER_LINE_START_COMMENT;
}
break;
case SCANNER_LINE_NUMBER_COMMENT:
if (ch>='0' && ch<='9') {
parser->line=parser->line*10+(ch-'0');
} else if (ch==' ') {
parser->scanner_state=SCANNER_FILE_NAME_COMMENT_START;
} else if (ch=='\n') {
parser->scanner_state=SCANNER_START;
} else if (ch==0) {
parser->scanner_state=SCANNER_START;
return W_EOF;
} else {
sgrep_error(sgrep,"Warning: '%s':%d: Malformed #line directive.\n",
string_to_char(parser->file),parser->errline);
parser->line=parser->errline;
parser->scanner_state=SCANNER_COMMENT;
}
break;
case SCANNER_FILE_NAME_COMMENT_START:
if (ch=='\"') {
string_clear(parser->file);
parser->scanner_state=SCANNER_FILE_NAME_COMMENT;
break;
}
sgrep_error(sgrep,"Warning: '%s':%d: Malformed #line directive.\n",
string_to_char(parser->file),parser->errline);
parser->line=parser->errline;
if (ch==0) {
parser->scanner_state=SCANNER_START;
return W_EOF;
break;
}
if (ch=='\n') {
parser->scanner_state=SCANNER_START;
break;
}
parser->scanner_state=SCANNER_COMMENT;
break;
case SCANNER_FILE_NAME_COMMENT:
if (ch=='\"') {
parser->scanner_state=SCANNER_COMMENT;
break;
}
if (ch=='\n' || ch==0) {
string_clear(parser->file);
string_cat(parser->file,"[unknown]");
sgrep_error(sgrep,"Warning: '%s':%d: Malformed #line directive.\n",
string_to_char(parser->file),parser->errline);
parser->line=parser->errline;
parser->scanner_state=SCANNER_START;
if (ch==0) return W_EOF;
break;
}
string_push(parser->file,ch);
break;
/* We read a number */
case SCANNER_NUMBER:
if ( ch<'0'|| ch>'9' )
{
parser->scanner_state=SCANNER_START;
str[i]=0;
*phrase=init_string(sgrep,i,str);
return W_NUMBER;
}
if (i==9)
{
real_parse_error(parser,"Too big number");
return W_PARSE_ERROR;
}
str[i++]=ch;
break;
}
ch=get_next_char(parser);
} while (1);
}
/*
* Shows a given error message & where it occurred
*/
void real_parse_error(Parser *parser, char *error)
{
char erlin[ELLENGTH+1];
int i;
SGREPDATA(parser);
if (parser->errcol-ELLENGTH+SHOWR>0)
parser->errind-=ELLENGTH-SHOWR;
else parser->errind-=parser->errcol;
for(i=0;i<ELLENGTH &&
parser->expr_str[i+parser->errind]
&& parser->expr_str[i+parser->errind]!='\n';
i++) {
erlin[i]=parser->expr_str[i+parser->errind];
if (erlin[i]=='\t') erlin[i]=' ';
}
erlin[i]=0;
if (string_len(parser->file)==0) {
sgrep_error(parser->sgrep,"Parse error in command line expression");
} else if (string_to_char(parser->file)[0]=='-') {
sgrep_error(parser->sgrep,"Parse error in stdin line %d",
parser->errline);
} else {
sgrep_error(parser->sgrep,"Parse error in file '%s' line %d",
string_to_char(parser->file),parser->errline);
}
sgrep_error(parser->sgrep," column %d :\n\t%s\n%s\n",
parser->errcol,
error,erlin);
if ( parser->errcol>ELLENGTH-SHOWR ) parser->errcol=ELLENGTH-SHOWR;
for (i=0;i<parser->errcol-1;i++) sgrep_error(sgrep," ");
sgrep_error(sgrep,"^\n");
}
/*
* Creates and initializez an operator node to parse tree
*/
ParseTreeNode *create_tree_node(Parser *parser, enum Oper oper)
{
ParseTreeNode *n;
SgrepData *sgrep=parser->sgrep;
assert(parser->nodes>=0);
if (parser->nodes==sizeof(parser->node_array)/
sizeof(ParseTreeNode *)) {
parse_error("Suspiciously many tree nodes\n");
return NULL;
}
n=sgrep_new(ParseTreeNode);
n->left=NULL;
n->right=NULL;
n->parent=NULL;
n->oper=oper;
n->number=-1;
n->leaf=NULL;
n->label_left=LABEL_NOTKNOWN;
n->label_right=LABEL_NOTKNOWN;
n->refcount=0;
n->result=NULL;
parser->node_array[parser->nodes++]=n;
return n;
}
/*
* Creates and initializes a leaf node to parse tree
*/
ParseTreeNode *create_leaf_node(Parser *parser,
enum Oper oper,
SgrepString *phrase, int phrase_label)
{
ParseTreeNode *n;
SgrepData *sgrep=parser->sgrep;
/* Create a leaf node */
n=create_tree_node(parser,oper);
if (!n) return NULL;
n->label_left=phrase_label;
/* Now create a phrase node for the phrase */
n->leaf=sgrep_new(struct PHRASE_NODE);
n->leaf->phrase=phrase;
n->leaf->regions=NULL;
n->result=NULL;
return n;
}
ParseTreeNode *new_string_phrase(Parser *parser,
SgrepString *phrase,
const char *typestr) {
ParseTreeNode *n;
SGREPDATA(parser);
if (phrase==NULL) {
phrase=init_string(sgrep,strlen(typestr),typestr);
} else {
push_front(phrase,typestr);
}
n=create_leaf_node(parser,PHRASE,phrase,LABEL_PHRASE);
if (!n) {
delete_string(phrase);
return NULL;
}
/* Put the new phrase node to phrase list */
n->leaf->next=parser->first_phrase;
parser->first_phrase=n->leaf;
return n;
}
/*
* Here starts recursive parser
*/
ParseTreeNode *parse_phrase(Parser *parser, const char *typestr) {
ParseTreeNode *n;
NEXT_TOKEN;
if (token!=W_LPAREN) parse_error("Expecting '('");
NEXT_TOKEN;
if (token!=W_PHRASE) parse_error("Expecting phrase string");
n=new_string_phrase(parser,parser->string_token,typestr);
if (!n) return NULL;
#if DEBUG
fprintf(stderr,"parse_phrase '%s'\n",n->leaf->phrase->s);
#endif
NEXT_TOKEN;
if (token!=W_RPAREN) parse_error("Expecting ')'");
NEXT_TOKEN;
return n;
}
/* production basic_expr->constant_list */
ParseTreeNode *parse_cons_list(Parser *parser)
{
int s,e,ps,pe;
char *cons_err="invalid constant region list";
ParseTreeNode *n;
RegionList *c_list;
SGREPDATA(parser);
n=create_leaf_node(parser,PHRASE,NULL,LABEL_CONS);
if (!n) return NULL;
NEXT_TOKEN;
c_list=n->leaf->regions=new_region_list(sgrep);
ps=-1;pe=-1;
while (token!=W_RBRACK) /* We can fall out here immediately,
which means we have empty list */
{
if (token!=W_LPAREN)
parse_error(cons_err);
NEXT_TOKEN;
if (token!=W_NUMBER)
parse_error(cons_err);
s=atoi(parser->string_token->s);
NEXT_TOKEN;
if (token!=W_COMMA)
parse_error(cons_err);
NEXT_TOKEN;
if (token!=W_NUMBER)
parse_error(cons_err);
e=atoi((char *)(parser->string_token->s));
NEXT_TOKEN;
if (token!=W_RPAREN)
parse_error(cons_err);
if (e<s)
parse_error("region end point must be greater than start point");
NEXT_TOKEN;
if (s<ps || (s==ps && e<=pe) )
parse_error("constant gc list must be sorted");
if (e<=pe || s==ps)
{
/* nesting detected */
c_list->nested=1;
}
add_region(c_list,s,e);
ps=s;pe=e;
}
parser->sgrep->statistics.constant_lists++;
NEXT_TOKEN;
return n;
}
/* Parses function(integer,expression) */
ParseTreeNode *parse_integer_function(Parser *parser,
enum Oper oper,
const char *name) {
ParseTreeNode *n=create_tree_node(parser, oper);
if (!n) return NULL;
/* Let's parse the parameters */
NEXT_TOKEN;
if (token!=W_LPAREN)
parse_error("( expected");
NEXT_TOKEN;
if (token!=W_NUMBER) {
char buf[1000];
sprintf(buf,"integer expected: %s(integer,expression)",name);
parse_error(buf);
}
n->number=atoi((char *)parser->string_token->s);
delete_string(parser->string_token);
parser->string_token=NULL;
if (n->number<0)
parse_error("Negative ints not implemented for last");
NEXT_TOKEN;
if (token!=W_COMMA) {
char buf[100];
sprintf(buf,"',' expected: %s(integer, expression)",name);
parse_error(buf);
return NULL;
}
NEXT_TOKEN;
n->left=parse_reg_expr(parser);
if (n->left==NULL) return NULL;
n->right=NULL;
if (token!=W_RPAREN)
parse_error(") expected");
NEXT_TOKEN;
return n;
}
ParseTreeNode *parse_int_oper_argument(Parser *parser,
enum Oper oper) {
ParseTreeNode *n=create_tree_node(parser,oper);
if (!n) return NULL;
NEXT_TOKEN;
if (token!=W_LPAREN) {
parse_error("Expecting '(' starting integer argument for operator");
return NULL;
}
NEXT_TOKEN;
if (token!=W_NUMBER) {
parse_error("Expecting integer argument for operator");
return NULL;
}
n->number=atoi(parser->string_token->s);
if (n->number<0) {
parse_error("Expecting integer value >=0");
return NULL;
}
delete_string(parser->string_token);
NEXT_TOKEN;
if (token!=W_RPAREN) {
parse_error("')' expected");
}
return n;
}
/* Which kind of basic expressions */
ParseTreeNode *parse_basic_expr(Parser *parser) {
ParseTreeNode *n;
switch (token) {
case W_LBRACK:
/* We got a constant region list */
return parse_cons_list(parser);
case W_CHARS:
/* reserved wors 'chars' was found */
parse_error("'chars' disabled until I figure out how to fix it (JJ)");
n=create_leaf_node(parser,PHRASE,NULL,LABEL_CHARS);
if (!n) return NULL;
/* we use already created list (see create_constant_lists() )*/
n->leaf->regions=parser->sgrep->chars_list;
NEXT_TOKEN;
return n;
case W_LPAREN:
NEXT_TOKEN;
n=parse_reg_expr(parser);
if (n==NULL) return NULL;
if (token!=W_RPAREN)
parse_error(") expected");
NEXT_TOKEN;
return n;
case W_OUTER:
case W_INNER:
case W_CONCAT:
/* So we have function. Let's create a tree node for it */
n=create_tree_node(parser,
(token==W_OUTER) ? OUTER:
((token==W_INNER) ? INNER:CONCAT) );
if (!n) return NULL;
/* Let's parse the parameter */
NEXT_TOKEN;
if (token!=W_LPAREN)
parse_error("( expected");
NEXT_TOKEN;
n->left=parse_reg_expr(parser);
if (n->left==NULL) return NULL;
n->right=NULL; /* Function has only one parameter */
if (token!=W_RPAREN)
parse_error(") expected");
NEXT_TOKEN;
return n;
case W_JOIN:
return parse_integer_function(parser,JOIN,"join");
case W_FIRST:
return parse_integer_function(parser,FIRST,"first");
case W_LAST:
return parse_integer_function(parser,LAST,"last");
case W_FIRST_BYTES:
return parse_integer_function(parser,FIRST_BYTES,"firs_bytes");
case W_LAST_BYTES:
return parse_integer_function(parser,LAST_BYTES,"last_bytes");
/* phrases */
case W_PHRASE:
/* A simple phrase */
n=new_string_phrase(parser,parser->string_token, "n");
if (!n) return NULL;
NEXT_TOKEN;
return n;
case W_START:
/* "start", first of possible regions */
n=new_string_phrase(parser,NULL,"#start");
if (!n) return NULL;
NEXT_TOKEN;
return n;
case W_END:
/* "end", last of possible regions */
n=new_string_phrase(parser,NULL, "#end");
if (!n) return NULL;
NEXT_TOKEN;
return n;
case W_COMMENT:
n=new_string_phrase(parser,NULL,"-");
if (!n) return NULL;
NEXT_TOKEN;
return n;
case W_ELEMENTS:
n=new_string_phrase(parser,NULL,"@elements");
if (!n) return NULL;
NEXT_TOKEN;
return n;
case W_PROLOG:
n=new_string_phrase(parser,NULL,"d!");
if (!n) return NULL;
NEXT_TOKEN;
return n;
case W_CDATA:
n=new_string_phrase(parser,NULL,"[CDATA");
if (!n) return NULL;
NEXT_TOKEN;
return n;
/* phrases with argument */
case W_RAW:
return parse_phrase(parser,"");
case W_FILE:
return parse_phrase(parser,"f");
case W_STRING:
return parse_phrase(parser,"n");
case W_REGEX:
return parse_phrase(parser,"r");
case W_DOCTYPE:
return parse_phrase(parser, "dn");
case W_DOCTYPE_PID:
return parse_phrase(parser, "dp");
case W_DOCTYPE_SID:
return parse_phrase(parser,"ds");
case W_ENTITY_DECLARATION:
return parse_phrase(parser,"!ed");
case W_ENTITY_LITERAL:
return parse_phrase(parser,"!el");
case W_ENTITY_PID:
return parse_phrase(parser,"!ep");
case W_ENTITY_SID:
return parse_phrase(parser,"!es");
case W_ENTITY_NDATA:
return parse_phrase(parser,"!en");
case W_PI:
return parse_phrase(parser,"?");
case W_ATTRIBUTE:
return parse_phrase(parser,"a");
case W_ATTVALUE:
return parse_phrase(parser,"v");
case W_STAG:
return parse_phrase(parser,"s");
case W_ETAG:
return parse_phrase(parser,"e");
case W_COMMENT_WORD:
return parse_phrase(parser,"c");
case W_WORD:
return parse_phrase(parser,"w");
case W_ENTITY:
return parse_phrase(parser,"&");
default:
parse_error("Basic expression expected\n");
}
/* Dummy return for keeping c++ compilers quiet */
return NULL;
}
/* Which kind region_expression */
ParseTreeNode *parse_reg_expr(Parser *parser)
{
ParseTreeNode *left;
if (token==W_EOF)
parse_error("Unexpected end of expression");
left=parse_basic_expr(parser);
if (left==NULL) return NULL;
if ( token==W_EOF || token==W_RPAREN ) return left;
return parse_oper_expr(parser,left);
}
/* Which kind of operator expression */
ParseTreeNode *parse_oper_expr(Parser *parser,ParseTreeNode *left)
{
ParseTreeNode *o=NULL;
switch (token)
{
case W_NEAR:
o=parse_int_oper_argument(parser,NEAR);
break;
case W_NEAR_BEFORE:
o=parse_int_oper_argument(parser,NEAR_BEFORE);
break;
case W_IN:
o=create_tree_node(parser,IN);
break;
case W_CONTAINING:
o=create_tree_node(parser,CONTAINING);
break;
/* PK Febr 95 */
case W_EQUAL:
o=create_tree_node(parser,EQUAL);
break;
/* PK Febr 95 */
case W_PARENTING:
o=create_tree_node(parser,PARENTING);
break;
case W_CHILDRENING:
o=create_tree_node(parser,CHILDRENING);
break;
case W_OR:
o=create_tree_node(parser,OR);
break;
case W_ORDERED:
o=create_tree_node(parser,ORDERED);
break;
case W_L_ORDERED:
o=create_tree_node(parser,L_ORDERED);
break;
case W_R_ORDERED:
o=create_tree_node(parser,R_ORDERED);
break;
case W_LR_ORDERED:
o=create_tree_node(parser,LR_ORDERED);
break;
case W_EXTRACTING:
o=create_tree_node(parser,EXTRACTING);
break;
case W_QUOTE:
o=create_tree_node(parser,QUOTE);
break;
case W_R_QUOTE:
o=create_tree_node(parser,R_QUOTE);
break;
case W_L_QUOTE:
o=create_tree_node(parser,L_QUOTE);
break;
case W_LR_QUOTE:
o=create_tree_node(parser,LR_QUOTE);
break;
case W_NOT:
NEXT_TOKEN;
if (token==W_CONTAINING) o=create_tree_node(parser,NOT_CONTAINING);
else if (token==W_IN) o=create_tree_node(parser,NOT_IN);
else if (token==W_EQUAL) o=create_tree_node(parser,NOT_EQUAL);
else parse_error("'not' must be followed by 'in', 'containing' or 'equal'");
break;
default:
parse_error("Operator expected");
}
if (!o) return NULL;
NEXT_TOKEN;
o->right=parse_basic_expr(parser);
if (o->right==NULL) return NULL;
o->left=left;
if (token==W_EOF || token==W_RPAREN) return o;
return parse_oper_expr(parser,o);
}
/* End of recursive parser */
/*
* Parses the given command string. Returns root node of the parse tree.
* phrase_list returns pointer to phrase list
*/
ParseTreeNode *parse_string(SgrepData *sgrep,const char *str,
struct PHRASE_NODE **phrase_list)
{
ParseTreeNode *root;
Parser parser_l;
Parser *parser=&parser_l;
parser->sgrep=sgrep;
parser->line=1;
parser->column=0;
parser->file=new_string(sgrep,8);
parser->expr_str=str;