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Ported to C.

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commit 53c9b7bcbd3aa0a56cc395937967da83a74c9bc5 0 parents
@theory authored
Showing with 5,939 additions and 0 deletions.
  1. +30 −0 Makefile
  2. +4,897 −0 lemon.c
  3. +850 −0 lempar.c
  4. +86 −0 main.c
  5. +43 −0 shellparser.y
  6. +33 −0 shellscanner.l
30 Makefile
@@ -0,0 +1,30 @@
+CFLAGS := $(CFLAGS) -std=c99
+
+shell: main.o shellparser.o shellscanner.o
+ $(CC) -o shell main.o shellparser.o shellscanner.o
+
+main.o: main.c shellparser.h shellscanner.h
+
+shellparser.o: shellparser.h
+
+shellparser.h: shellparser.y lemon
+ ./lemon shellparser.y
+
+shellscanner.o: shellscanner.h
+
+shellscanner.h: shellscanner.l
+ flex --outfile=shellscanner.c --header-file=shellscanner.h shellscanner.l
+
+# Prevent yacc from trying to build parsers.
+# http://stackoverflow.com/a/5395195/79202
+%.c: %.y
+
+lemon: lemon.c
+ $(CC) -o lemon lemon.c
+
+.PHONY: clean
+clean:
+ rm -f *.o
+ rm -f shellscanner.c shellscanner.h
+ rm -f shellparser.c shellparser.h shellparser.out
+ rm -f shell lemon
4,897 lemon.c
4,897 additions, 0 deletions not shown
850 lempar.c
@@ -0,0 +1,850 @@
+/* Driver template for the LEMON parser generator.
+** The author disclaims copyright to this source code.
+*/
+/* First off, code is included that follows the "include" declaration
+** in the input grammar file. */
+#include <stdio.h>
+%%
+/* Next is all token values, in a form suitable for use by makeheaders.
+** This section will be null unless lemon is run with the -m switch.
+*/
+/*
+** These constants (all generated automatically by the parser generator)
+** specify the various kinds of tokens (terminals) that the parser
+** understands.
+**
+** Each symbol here is a terminal symbol in the grammar.
+*/
+%%
+/* Make sure the INTERFACE macro is defined.
+*/
+#ifndef INTERFACE
+# define INTERFACE 1
+#endif
+/* The next thing included is series of defines which control
+** various aspects of the generated parser.
+** YYCODETYPE is the data type used for storing terminal
+** and nonterminal numbers. "unsigned char" is
+** used if there are fewer than 250 terminals
+** and nonterminals. "int" is used otherwise.
+** YYNOCODE is a number of type YYCODETYPE which corresponds
+** to no legal terminal or nonterminal number. This
+** number is used to fill in empty slots of the hash
+** table.
+** YYFALLBACK If defined, this indicates that one or more tokens
+** have fall-back values which should be used if the
+** original value of the token will not parse.
+** YYACTIONTYPE is the data type used for storing terminal
+** and nonterminal numbers. "unsigned char" is
+** used if there are fewer than 250 rules and
+** states combined. "int" is used otherwise.
+** ParseTOKENTYPE is the data type used for minor tokens given
+** directly to the parser from the tokenizer.
+** YYMINORTYPE is the data type used for all minor tokens.
+** This is typically a union of many types, one of
+** which is ParseTOKENTYPE. The entry in the union
+** for base tokens is called "yy0".
+** YYSTACKDEPTH is the maximum depth of the parser's stack. If
+** zero the stack is dynamically sized using realloc()
+** ParseARG_SDECL A static variable declaration for the %extra_argument
+** ParseARG_PDECL A parameter declaration for the %extra_argument
+** ParseARG_STORE Code to store %extra_argument into yypParser
+** ParseARG_FETCH Code to extract %extra_argument from yypParser
+** YYNSTATE the combined number of states.
+** YYNRULE the number of rules in the grammar
+** YYERRORSYMBOL is the code number of the error symbol. If not
+** defined, then do no error processing.
+*/
+%%
+#define YY_NO_ACTION (YYNSTATE+YYNRULE+2)
+#define YY_ACCEPT_ACTION (YYNSTATE+YYNRULE+1)
+#define YY_ERROR_ACTION (YYNSTATE+YYNRULE)
+
+/* The yyzerominor constant is used to initialize instances of
+** YYMINORTYPE objects to zero. */
+static const YYMINORTYPE yyzerominor = { 0 };
+
+/* Define the yytestcase() macro to be a no-op if is not already defined
+** otherwise.
+**
+** Applications can choose to define yytestcase() in the %include section
+** to a macro that can assist in verifying code coverage. For production
+** code the yytestcase() macro should be turned off. But it is useful
+** for testing.
+*/
+#ifndef yytestcase
+# define yytestcase(X)
+#endif
+
+
+/* Next are the tables used to determine what action to take based on the
+** current state and lookahead token. These tables are used to implement
+** functions that take a state number and lookahead value and return an
+** action integer.
+**
+** Suppose the action integer is N. Then the action is determined as
+** follows
+**
+** 0 <= N < YYNSTATE Shift N. That is, push the lookahead
+** token onto the stack and goto state N.
+**
+** YYNSTATE <= N < YYNSTATE+YYNRULE Reduce by rule N-YYNSTATE.
+**
+** N == YYNSTATE+YYNRULE A syntax error has occurred.
+**
+** N == YYNSTATE+YYNRULE+1 The parser accepts its input.
+**
+** N == YYNSTATE+YYNRULE+2 No such action. Denotes unused
+** slots in the yy_action[] table.
+**
+** The action table is constructed as a single large table named yy_action[].
+** Given state S and lookahead X, the action is computed as
+**
+** yy_action[ yy_shift_ofst[S] + X ]
+**
+** If the index value yy_shift_ofst[S]+X is out of range or if the value
+** yy_lookahead[yy_shift_ofst[S]+X] is not equal to X or if yy_shift_ofst[S]
+** is equal to YY_SHIFT_USE_DFLT, it means that the action is not in the table
+** and that yy_default[S] should be used instead.
+**
+** The formula above is for computing the action when the lookahead is
+** a terminal symbol. If the lookahead is a non-terminal (as occurs after
+** a reduce action) then the yy_reduce_ofst[] array is used in place of
+** the yy_shift_ofst[] array and YY_REDUCE_USE_DFLT is used in place of
+** YY_SHIFT_USE_DFLT.
+**
+** The following are the tables generated in this section:
+**
+** yy_action[] A single table containing all actions.
+** yy_lookahead[] A table containing the lookahead for each entry in
+** yy_action. Used to detect hash collisions.
+** yy_shift_ofst[] For each state, the offset into yy_action for
+** shifting terminals.
+** yy_reduce_ofst[] For each state, the offset into yy_action for
+** shifting non-terminals after a reduce.
+** yy_default[] Default action for each state.
+*/
+%%
+
+/* The next table maps tokens into fallback tokens. If a construct
+** like the following:
+**
+** %fallback ID X Y Z.
+**
+** appears in the grammar, then ID becomes a fallback token for X, Y,
+** and Z. Whenever one of the tokens X, Y, or Z is input to the parser
+** but it does not parse, the type of the token is changed to ID and
+** the parse is retried before an error is thrown.
+*/
+#ifdef YYFALLBACK
+static const YYCODETYPE yyFallback[] = {
+%%
+};
+#endif /* YYFALLBACK */
+
+/* The following structure represents a single element of the
+** parser's stack. Information stored includes:
+**
+** + The state number for the parser at this level of the stack.
+**
+** + The value of the token stored at this level of the stack.
+** (In other words, the "major" token.)
+**
+** + The semantic value stored at this level of the stack. This is
+** the information used by the action routines in the grammar.
+** It is sometimes called the "minor" token.
+*/
+struct yyStackEntry {
+ YYACTIONTYPE stateno; /* The state-number */
+ YYCODETYPE major; /* The major token value. This is the code
+ ** number for the token at this stack level */
+ YYMINORTYPE minor; /* The user-supplied minor token value. This
+ ** is the value of the token */
+};
+typedef struct yyStackEntry yyStackEntry;
+
+/* The state of the parser is completely contained in an instance of
+** the following structure */
+struct yyParser {
+ int yyidx; /* Index of top element in stack */
+#ifdef YYTRACKMAXSTACKDEPTH
+ int yyidxMax; /* Maximum value of yyidx */
+#endif
+ int yyerrcnt; /* Shifts left before out of the error */
+ ParseARG_SDECL /* A place to hold %extra_argument */
+#if YYSTACKDEPTH<=0
+ int yystksz; /* Current side of the stack */
+ yyStackEntry *yystack; /* The parser's stack */
+#else
+ yyStackEntry yystack[YYSTACKDEPTH]; /* The parser's stack */
+#endif
+};
+typedef struct yyParser yyParser;
+
+#ifndef NDEBUG
+#include <stdio.h>
+static FILE *yyTraceFILE = 0;
+static char *yyTracePrompt = 0;
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/*
+** Turn parser tracing on by giving a stream to which to write the trace
+** and a prompt to preface each trace message. Tracing is turned off
+** by making either argument NULL
+**
+** Inputs:
+** <ul>
+** <li> A FILE* to which trace output should be written.
+** If NULL, then tracing is turned off.
+** <li> A prefix string written at the beginning of every
+** line of trace output. If NULL, then tracing is
+** turned off.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+void ParseTrace(FILE *TraceFILE, char *zTracePrompt){
+ yyTraceFILE = TraceFILE;
+ yyTracePrompt = zTracePrompt;
+ if( yyTraceFILE==0 ) yyTracePrompt = 0;
+ else if( yyTracePrompt==0 ) yyTraceFILE = 0;
+}
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/* For tracing shifts, the names of all terminals and nonterminals
+** are required. The following table supplies these names */
+static const char *const yyTokenName[] = {
+%%
+};
+#endif /* NDEBUG */
+
+#ifndef NDEBUG
+/* For tracing reduce actions, the names of all rules are required.
+*/
+static const char *const yyRuleName[] = {
+%%
+};
+#endif /* NDEBUG */
+
+
+#if YYSTACKDEPTH<=0
+/*
+** Try to increase the size of the parser stack.
+*/
+static void yyGrowStack(yyParser *p){
+ int newSize;
+ yyStackEntry *pNew;
+
+ newSize = p->yystksz*2 + 100;
+ pNew = realloc(p->yystack, newSize*sizeof(pNew[0]));
+ if( pNew ){
+ p->yystack = pNew;
+ p->yystksz = newSize;
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE,"%sStack grows to %d entries!\n",
+ yyTracePrompt, p->yystksz);
+ }
+#endif
+ }
+}
+#endif
+
+/*
+** This function allocates a new parser.
+** The only argument is a pointer to a function which works like
+** malloc.
+**
+** Inputs:
+** A pointer to the function used to allocate memory.
+**
+** Outputs:
+** A pointer to a parser. This pointer is used in subsequent calls
+** to Parse and ParseFree.
+*/
+void *ParseAlloc(void *(*mallocProc)(size_t)){
+ yyParser *pParser;
+ pParser = (yyParser*)(*mallocProc)( (size_t)sizeof(yyParser) );
+ if( pParser ){
+ pParser->yyidx = -1;
+#ifdef YYTRACKMAXSTACKDEPTH
+ pParser->yyidxMax = 0;
+#endif
+#if YYSTACKDEPTH<=0
+ pParser->yystack = NULL;
+ pParser->yystksz = 0;
+ yyGrowStack(pParser);
+#endif
+ }
+ return pParser;
+}
+
+/* The following function deletes the value associated with a
+** symbol. The symbol can be either a terminal or nonterminal.
+** "yymajor" is the symbol code, and "yypminor" is a pointer to
+** the value.
+*/
+static void yy_destructor(
+ yyParser *yypParser, /* The parser */
+ YYCODETYPE yymajor, /* Type code for object to destroy */
+ YYMINORTYPE *yypminor /* The object to be destroyed */
+){
+ ParseARG_FETCH;
+ switch( yymajor ){
+ /* Here is inserted the actions which take place when a
+ ** terminal or non-terminal is destroyed. This can happen
+ ** when the symbol is popped from the stack during a
+ ** reduce or during error processing or when a parser is
+ ** being destroyed before it is finished parsing.
+ **
+ ** Note: during a reduce, the only symbols destroyed are those
+ ** which appear on the RHS of the rule, but which are not used
+ ** inside the C code.
+ */
+%%
+ default: break; /* If no destructor action specified: do nothing */
+ }
+}
+
+/*
+** Pop the parser's stack once.
+**
+** If there is a destructor routine associated with the token which
+** is popped from the stack, then call it.
+**
+** Return the major token number for the symbol popped.
+*/
+static int yy_pop_parser_stack(yyParser *pParser){
+ YYCODETYPE yymajor;
+ yyStackEntry *yytos = &pParser->yystack[pParser->yyidx];
+
+ if( pParser->yyidx<0 ) return 0;
+#ifndef NDEBUG
+ if( yyTraceFILE && pParser->yyidx>=0 ){
+ fprintf(yyTraceFILE,"%sPopping %s\n",
+ yyTracePrompt,
+ yyTokenName[yytos->major]);
+ }
+#endif
+ yymajor = yytos->major;
+ yy_destructor(pParser, yymajor, &yytos->minor);
+ pParser->yyidx--;
+ return yymajor;
+}
+
+/*
+** Deallocate and destroy a parser. Destructors are all called for
+** all stack elements before shutting the parser down.
+**
+** Inputs:
+** <ul>
+** <li> A pointer to the parser. This should be a pointer
+** obtained from ParseAlloc.
+** <li> A pointer to a function used to reclaim memory obtained
+** from malloc.
+** </ul>
+*/
+void ParseFree(
+ void *p, /* The parser to be deleted */
+ void (*freeProc)(void*) /* Function used to reclaim memory */
+){
+ yyParser *pParser = (yyParser*)p;
+ if( pParser==0 ) return;
+ while( pParser->yyidx>=0 ) yy_pop_parser_stack(pParser);
+#if YYSTACKDEPTH<=0
+ free(pParser->yystack);
+#endif
+ (*freeProc)((void*)pParser);
+}
+
+/*
+** Return the peak depth of the stack for a parser.
+*/
+#ifdef YYTRACKMAXSTACKDEPTH
+int ParseStackPeak(void *p){
+ yyParser *pParser = (yyParser*)p;
+ return pParser->yyidxMax;
+}
+#endif
+
+/*
+** Find the appropriate action for a parser given the terminal
+** look-ahead token iLookAhead.
+**
+** If the look-ahead token is YYNOCODE, then check to see if the action is
+** independent of the look-ahead. If it is, return the action, otherwise
+** return YY_NO_ACTION.
+*/
+static int yy_find_shift_action(
+ yyParser *pParser, /* The parser */
+ YYCODETYPE iLookAhead /* The look-ahead token */
+){
+ int i;
+ int stateno = pParser->yystack[pParser->yyidx].stateno;
+
+ if( stateno>YY_SHIFT_COUNT
+ || (i = yy_shift_ofst[stateno])==YY_SHIFT_USE_DFLT ){
+ return yy_default[stateno];
+ }
+ assert( iLookAhead!=YYNOCODE );
+ i += iLookAhead;
+ if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
+ if( iLookAhead>0 ){
+#ifdef YYFALLBACK
+ YYCODETYPE iFallback; /* Fallback token */
+ if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
+ && (iFallback = yyFallback[iLookAhead])!=0 ){
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
+ yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
+ }
+#endif
+ return yy_find_shift_action(pParser, iFallback);
+ }
+#endif
+#ifdef YYWILDCARD
+ {
+ int j = i - iLookAhead + YYWILDCARD;
+ if(
+#if YY_SHIFT_MIN+YYWILDCARD<0
+ j>=0 &&
+#endif
+#if YY_SHIFT_MAX+YYWILDCARD>=YY_ACTTAB_COUNT
+ j<YY_ACTTAB_COUNT &&
+#endif
+ yy_lookahead[j]==YYWILDCARD
+ ){
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
+ yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[YYWILDCARD]);
+ }
+#endif /* NDEBUG */
+ return yy_action[j];
+ }
+ }
+#endif /* YYWILDCARD */
+ }
+ return yy_default[stateno];
+ }else{
+ return yy_action[i];
+ }
+}
+
+/*
+** Find the appropriate action for a parser given the non-terminal
+** look-ahead token iLookAhead.
+**
+** If the look-ahead token is YYNOCODE, then check to see if the action is
+** independent of the look-ahead. If it is, return the action, otherwise
+** return YY_NO_ACTION.
+*/
+static int yy_find_reduce_action(
+ int stateno, /* Current state number */
+ YYCODETYPE iLookAhead /* The look-ahead token */
+){
+ int i;
+#ifdef YYERRORSYMBOL
+ if( stateno>YY_REDUCE_COUNT ){
+ return yy_default[stateno];
+ }
+#else
+ assert( stateno<=YY_REDUCE_COUNT );
+#endif
+ i = yy_reduce_ofst[stateno];
+ assert( i!=YY_REDUCE_USE_DFLT );
+ assert( iLookAhead!=YYNOCODE );
+ i += iLookAhead;
+#ifdef YYERRORSYMBOL
+ if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
+ return yy_default[stateno];
+ }
+#else
+ assert( i>=0 && i<YY_ACTTAB_COUNT );
+ assert( yy_lookahead[i]==iLookAhead );
+#endif
+ return yy_action[i];
+}
+
+/*
+** The following routine is called if the stack overflows.
+*/
+static void yyStackOverflow(yyParser *yypParser, YYMINORTYPE *yypMinor){
+ ParseARG_FETCH;
+ yypParser->yyidx--;
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE,"%sStack Overflow!\n",yyTracePrompt);
+ }
+#endif
+ while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
+ /* Here code is inserted which will execute if the parser
+ ** stack every overflows */
+%%
+ ParseARG_STORE; /* Suppress warning about unused %extra_argument var */
+}
+
+/*
+** Perform a shift action.
+*/
+static void yy_shift(
+ yyParser *yypParser, /* The parser to be shifted */
+ int yyNewState, /* The new state to shift in */
+ int yyMajor, /* The major token to shift in */
+ YYMINORTYPE *yypMinor /* Pointer to the minor token to shift in */
+){
+ yyStackEntry *yytos;
+ yypParser->yyidx++;
+#ifdef YYTRACKMAXSTACKDEPTH
+ if( yypParser->yyidx>yypParser->yyidxMax ){
+ yypParser->yyidxMax = yypParser->yyidx;
+ }
+#endif
+#if YYSTACKDEPTH>0
+ if( yypParser->yyidx>=YYSTACKDEPTH ){
+ yyStackOverflow(yypParser, yypMinor);
+ return;
+ }
+#else
+ if( yypParser->yyidx>=yypParser->yystksz ){
+ yyGrowStack(yypParser);
+ if( yypParser->yyidx>=yypParser->yystksz ){
+ yyStackOverflow(yypParser, yypMinor);
+ return;
+ }
+ }
+#endif
+ yytos = &yypParser->yystack[yypParser->yyidx];
+ yytos->stateno = (YYACTIONTYPE)yyNewState;
+ yytos->major = (YYCODETYPE)yyMajor;
+ yytos->minor = *yypMinor;
+#ifndef NDEBUG
+ if( yyTraceFILE && yypParser->yyidx>0 ){
+ int i;
+ fprintf(yyTraceFILE,"%sShift %d\n",yyTracePrompt,yyNewState);
+ fprintf(yyTraceFILE,"%sStack:",yyTracePrompt);
+ for(i=1; i<=yypParser->yyidx; i++)
+ fprintf(yyTraceFILE," %s",yyTokenName[yypParser->yystack[i].major]);
+ fprintf(yyTraceFILE,"\n");
+ }
+#endif
+}
+
+/* The following table contains information about every rule that
+** is used during the reduce.
+*/
+static const struct {
+ YYCODETYPE lhs; /* Symbol on the left-hand side of the rule */
+ unsigned char nrhs; /* Number of right-hand side symbols in the rule */
+} yyRuleInfo[] = {
+%%
+};
+
+static void yy_accept(yyParser*); /* Forward Declaration */
+
+/*
+** Perform a reduce action and the shift that must immediately
+** follow the reduce.
+*/
+static void yy_reduce(
+ yyParser *yypParser, /* The parser */
+ int yyruleno /* Number of the rule by which to reduce */
+){
+ int yygoto; /* The next state */
+ int yyact; /* The next action */
+ YYMINORTYPE yygotominor; /* The LHS of the rule reduced */
+ yyStackEntry *yymsp; /* The top of the parser's stack */
+ int yysize; /* Amount to pop the stack */
+ ParseARG_FETCH;
+ yymsp = &yypParser->yystack[yypParser->yyidx];
+#ifndef NDEBUG
+ if( yyTraceFILE && yyruleno>=0
+ && yyruleno<(int)(sizeof(yyRuleName)/sizeof(yyRuleName[0])) ){
+ fprintf(yyTraceFILE, "%sReduce [%s].\n", yyTracePrompt,
+ yyRuleName[yyruleno]);
+ }
+#endif /* NDEBUG */
+
+ /* Silence complaints from purify about yygotominor being uninitialized
+ ** in some cases when it is copied into the stack after the following
+ ** switch. yygotominor is uninitialized when a rule reduces that does
+ ** not set the value of its left-hand side nonterminal. Leaving the
+ ** value of the nonterminal uninitialized is utterly harmless as long
+ ** as the value is never used. So really the only thing this code
+ ** accomplishes is to quieten purify.
+ **
+ ** 2007-01-16: The wireshark project (www.wireshark.org) reports that
+ ** without this code, their parser segfaults. I'm not sure what there
+ ** parser is doing to make this happen. This is the second bug report
+ ** from wireshark this week. Clearly they are stressing Lemon in ways
+ ** that it has not been previously stressed... (SQLite ticket #2172)
+ */
+ /*memset(&yygotominor, 0, sizeof(yygotominor));*/
+ yygotominor = yyzerominor;
+
+
+ switch( yyruleno ){
+ /* Beginning here are the reduction cases. A typical example
+ ** follows:
+ ** case 0:
+ ** #line <lineno> <grammarfile>
+ ** { ... } // User supplied code
+ ** #line <lineno> <thisfile>
+ ** break;
+ */
+%%
+ };
+ yygoto = yyRuleInfo[yyruleno].lhs;
+ yysize = yyRuleInfo[yyruleno].nrhs;
+ yypParser->yyidx -= yysize;
+ yyact = yy_find_reduce_action(yymsp[-yysize].stateno,(YYCODETYPE)yygoto);
+ if( yyact < YYNSTATE ){
+#ifdef NDEBUG
+ /* If we are not debugging and the reduce action popped at least
+ ** one element off the stack, then we can push the new element back
+ ** onto the stack here, and skip the stack overflow test in yy_shift().
+ ** That gives a significant speed improvement. */
+ if( yysize ){
+ yypParser->yyidx++;
+ yymsp -= yysize-1;
+ yymsp->stateno = (YYACTIONTYPE)yyact;
+ yymsp->major = (YYCODETYPE)yygoto;
+ yymsp->minor = yygotominor;
+ }else
+#endif
+ {
+ yy_shift(yypParser,yyact,yygoto,&yygotominor);
+ }
+ }else{
+ assert( yyact == YYNSTATE + YYNRULE + 1 );
+ yy_accept(yypParser);
+ }
+}
+
+/*
+** The following code executes when the parse fails
+*/
+#ifndef YYNOERRORRECOVERY
+static void yy_parse_failed(
+ yyParser *yypParser /* The parser */
+){
+ ParseARG_FETCH;
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE,"%sFail!\n",yyTracePrompt);
+ }
+#endif
+ while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
+ /* Here code is inserted which will be executed whenever the
+ ** parser fails */
+%%
+ ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
+}
+#endif /* YYNOERRORRECOVERY */
+
+/*
+** The following code executes when a syntax error first occurs.
+*/
+static void yy_syntax_error(
+ yyParser *yypParser, /* The parser */
+ int yymajor, /* The major type of the error token */
+ YYMINORTYPE yyminor /* The minor type of the error token */
+){
+ ParseARG_FETCH;
+#define TOKEN (yyminor.yy0)
+%%
+ ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
+}
+
+/*
+** The following is executed when the parser accepts
+*/
+static void yy_accept(
+ yyParser *yypParser /* The parser */
+){
+ ParseARG_FETCH;
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE,"%sAccept!\n",yyTracePrompt);
+ }
+#endif
+ while( yypParser->yyidx>=0 ) yy_pop_parser_stack(yypParser);
+ /* Here code is inserted which will be executed whenever the
+ ** parser accepts */
+%%
+ ParseARG_STORE; /* Suppress warning about unused %extra_argument variable */
+}
+
+/* The main parser program.
+** The first argument is a pointer to a structure obtained from
+** "ParseAlloc" which describes the current state of the parser.
+** The second argument is the major token number. The third is
+** the minor token. The fourth optional argument is whatever the
+** user wants (and specified in the grammar) and is available for
+** use by the action routines.
+**
+** Inputs:
+** <ul>
+** <li> A pointer to the parser (an opaque structure.)
+** <li> The major token number.
+** <li> The minor token number.
+** <li> An option argument of a grammar-specified type.
+** </ul>
+**
+** Outputs:
+** None.
+*/
+void Parse(
+ void *yyp, /* The parser */
+ int yymajor, /* The major token code number */
+ ParseTOKENTYPE yyminor /* The value for the token */
+ ParseARG_PDECL /* Optional %extra_argument parameter */
+){
+ YYMINORTYPE yyminorunion;
+ int yyact; /* The parser action. */
+ int yyendofinput; /* True if we are at the end of input */
+#ifdef YYERRORSYMBOL
+ int yyerrorhit = 0; /* True if yymajor has invoked an error */
+#endif
+ yyParser *yypParser; /* The parser */
+
+ /* (re)initialize the parser, if necessary */
+ yypParser = (yyParser*)yyp;
+ if( yypParser->yyidx<0 ){
+#if YYSTACKDEPTH<=0
+ if( yypParser->yystksz <=0 ){
+ /*memset(&yyminorunion, 0, sizeof(yyminorunion));*/
+ yyminorunion = yyzerominor;
+ yyStackOverflow(yypParser, &yyminorunion);
+ return;
+ }
+#endif
+ yypParser->yyidx = 0;
+ yypParser->yyerrcnt = -1;
+ yypParser->yystack[0].stateno = 0;
+ yypParser->yystack[0].major = 0;
+ }
+ yyminorunion.yy0 = yyminor;
+ yyendofinput = (yymajor==0);
+ ParseARG_STORE;
+
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE,"%sInput %s\n",yyTracePrompt,yyTokenName[yymajor]);
+ }
+#endif
+
+ do{
+ yyact = yy_find_shift_action(yypParser,(YYCODETYPE)yymajor);
+ if( yyact<YYNSTATE ){
+ assert( !yyendofinput ); /* Impossible to shift the $ token */
+ yy_shift(yypParser,yyact,yymajor,&yyminorunion);
+ yypParser->yyerrcnt--;
+ yymajor = YYNOCODE;
+ }else if( yyact < YYNSTATE + YYNRULE ){
+ yy_reduce(yypParser,yyact-YYNSTATE);
+ }else{
+ assert( yyact == YY_ERROR_ACTION );
+#ifdef YYERRORSYMBOL
+ int yymx;
+#endif
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE,"%sSyntax Error!\n",yyTracePrompt);
+ }
+#endif
+#ifdef YYERRORSYMBOL
+ /* A syntax error has occurred.
+ ** The response to an error depends upon whether or not the
+ ** grammar defines an error token "ERROR".
+ **
+ ** This is what we do if the grammar does define ERROR:
+ **
+ ** * Call the %syntax_error function.
+ **
+ ** * Begin popping the stack until we enter a state where
+ ** it is legal to shift the error symbol, then shift
+ ** the error symbol.
+ **
+ ** * Set the error count to three.
+ **
+ ** * Begin accepting and shifting new tokens. No new error
+ ** processing will occur until three tokens have been
+ ** shifted successfully.
+ **
+ */
+ if( yypParser->yyerrcnt<0 ){
+ yy_syntax_error(yypParser,yymajor,yyminorunion);
+ }
+ yymx = yypParser->yystack[yypParser->yyidx].major;
+ if( yymx==YYERRORSYMBOL || yyerrorhit ){
+#ifndef NDEBUG
+ if( yyTraceFILE ){
+ fprintf(yyTraceFILE,"%sDiscard input token %s\n",
+ yyTracePrompt,yyTokenName[yymajor]);
+ }
+#endif
+ yy_destructor(yypParser, (YYCODETYPE)yymajor,&yyminorunion);
+ yymajor = YYNOCODE;
+ }else{
+ while(
+ yypParser->yyidx >= 0 &&
+ yymx != YYERRORSYMBOL &&
+ (yyact = yy_find_reduce_action(
+ yypParser->yystack[yypParser->yyidx].stateno,
+ YYERRORSYMBOL)) >= YYNSTATE
+ ){
+ yy_pop_parser_stack(yypParser);
+ }
+ if( yypParser->yyidx < 0 || yymajor==0 ){
+ yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+ yy_parse_failed(yypParser);
+ yymajor = YYNOCODE;
+ }else if( yymx!=YYERRORSYMBOL ){
+ YYMINORTYPE u2;
+ u2.YYERRSYMDT = 0;
+ yy_shift(yypParser,yyact,YYERRORSYMBOL,&u2);
+ }
+ }
+ yypParser->yyerrcnt = 3;
+ yyerrorhit = 1;
+#elif defined(YYNOERRORRECOVERY)
+ /* If the YYNOERRORRECOVERY macro is defined, then do not attempt to
+ ** do any kind of error recovery. Instead, simply invoke the syntax
+ ** error routine and continue going as if nothing had happened.
+ **
+ ** Applications can set this macro (for example inside %include) if
+ ** they intend to abandon the parse upon the first syntax error seen.
+ */
+ yy_syntax_error(yypParser,yymajor,yyminorunion);
+ yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+ yymajor = YYNOCODE;
+
+#else /* YYERRORSYMBOL is not defined */
+ /* This is what we do if the grammar does not define ERROR:
+ **
+ ** * Report an error message, and throw away the input token.
+ **
+ ** * If the input token is $, then fail the parse.
+ **
+ ** As before, subsequent error messages are suppressed until
+ ** three input tokens have been successfully shifted.
+ */
+ if( yypParser->yyerrcnt<=0 ){
+ yy_syntax_error(yypParser,yymajor,yyminorunion);
+ }
+ yypParser->yyerrcnt = 3;
+ yy_destructor(yypParser,(YYCODETYPE)yymajor,&yyminorunion);
+ if( yyendofinput ){
+ yy_parse_failed(yypParser);
+ }
+ yymajor = YYNOCODE;
+#endif
+ }
+ }while( yymajor!=YYNOCODE && yypParser->yyidx>=0 );
+ return;
+}
86 main.c
@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "shellparser.h"
+#include "shellscanner.h"
+
+void* ParseAlloc(void* (*allocProc)(size_t));
+void* Parse(void*, int, const char*);
+void* ParseFree(void*, void(*freeProc)(void*));
+
+void parse(const char *commandLine) {
+ // Set up the scanner
+ yyscan_t scanner;
+ yylex_init(&scanner);
+ YY_BUFFER_STATE bufferState = yy_scan_string(commandLine, scanner);
+
+ // Set up the parser
+ void* shellParser = ParseAlloc(malloc);
+
+ int lexCode;
+ do {
+ lexCode = yylex(scanner);
+ Parse(shellParser, lexCode, NULL);
+ } while (lexCode > 0);
+
+ if (-1 == lexCode) {
+ fprintf(stderr, "The scanner encountered an error.\n");
+ }
+
+ // Cleanup the scanner and parser
+ yy_delete_buffer(bufferState, scanner);
+ yylex_destroy(scanner);
+ ParseFree(shellParser, free);
+}
+
+// Borrowed from http://stackoverflow.com/a/314422/79202.
+char * getline(void) {
+ char * line = malloc(100), * linep = line;
+ size_t lenmax = 100, len = lenmax;
+ int c;
+
+ if(line == NULL)
+ return NULL;
+
+ for(;;) {
+ c = fgetc(stdin);
+ if(c == EOF)
+ break;
+
+ if(--len == 0) {
+ len = lenmax;
+ char * linen = realloc(linep, lenmax *= 2);
+
+ if(linen == NULL) {
+ free(linep);
+ return NULL;
+ }
+ line = linen + (line - linep);
+ linep = linen;
+ }
+
+ if((*line++ = c) == '\n')
+ break;
+ }
+ *line = '\0';
+ return linep;
+}
+
+int main(int argc, char** argv) {
+ void* shellParser = ParseAlloc(malloc);
+ char *line;
+ printf("> ");
+ while ( line = getline() ) {
+ parse(line);
+ printf("> ");
+ }
+ return 0;
+
+ // Simulate a command line such as "cat main.cpp | wc"
+ /* Parse(sheallParser, FILENAME, "cat"); */
+ /* Parse(shellParser, FILENAME, "main.c"); */
+ /* Parse(shellParser, PIPE, 0); */
+ /* Parse(shellParser, FILENAME, "wc"); */
+ /* Parse(shellParser, 0, 0); // Signal end of tokens */
+ /* ParseFree(shellParser, free); */
+ /* return 0; */
+}
43 shellparser.y
@@ -0,0 +1,43 @@
+%include {
+#include <stdio.h>
+#include <assert.h>
+}
+
+%token_type {const char*}
+
+%syntax_error
+{
+ fprintf(stderr, "Error parsing command\n");
+}
+
+start ::= commandList .
+{
+}
+commandList ::= command PIPE commandList .
+{
+}
+commandList ::= command .
+{
+}
+
+command ::= FILENAME argumentList .
+{
+}
+command ::= FILENAME .
+{
+}
+
+argumentList ::= argument argumentList .
+{
+}
+argumentList ::= argument .
+{
+}
+argument ::= ARGUMENT .
+{
+}
+argument ::= FILENAME .
+{
+}
+
+
33 shellscanner.l
@@ -0,0 +1,33 @@
+%{
+ #include "shellparser.h"
+%}
+
+%option reentrant
+%option noyywrap
+
+%x SINGLE_QUOTED
+%x DOUBLE_QUOTED
+
+%%
+
+"|" { return PIPE; }
+
+[ \t\n\r] { }
+
+[a-zA-Z0-9_\.\-]+ { return FILENAME; }
+
+['] { BEGIN(SINGLE_QUOTED); }
+<SINGLE_QUOTED>[^']+ { }
+<SINGLE_QUOTED>['] { BEGIN(INITIAL); return ARGUMENT; }
+<SINGLE_QUOTED><<EOF>> { return -1; }
+
+["] { BEGIN(DOUBLE_QUOTED); }
+<DOUBLE_QUOTED>[^"]+ { }
+<DOUBLE_QUOTED>["] { BEGIN(INITIAL); return ARGUMENT; }
+<DOUBLE_QUOTED><<EOF>> { return -1; }
+
+[^ \t\r\n|'"]+ { return ARGUMENT; }
+
+%%
+
+
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