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lex.ll @ 982832e

ADTaaron-thesisarm-ehast-experimentalcleanup-dtorsdeferred_resndemanglerenumforall-pointer-decayjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-exprnew-envno_listpersistent-indexerpthread-emulationqualifiedEnumresolv-newwith_gc

Last change on this file since 982832e was f4b77f2, checked in by Peter A. Buhr <pabuhr@…>, 7 years ago
fix rules for parsing floating-point literals
Property mode set to `100644`
File size: 17.7 KB

Line
1	/*
2	* Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
3	*
4	* The contents of this file are covered under the licence agreement in the
5	* file "LICENCE" distributed with Cforall.
6	*
7	* lex.ll --
8	*
9	* Author : Peter A. Buhr
10	* Created On : Sat Sep 22 08:58:10 2001
11	* Last Modified By : Peter A. Buhr
12	* Last Modified On : Sun Sep 10 22:29:15 2017
13	* Update Count : 620
14	*/
15
16	%option yylineno
17	%option noyywrap
18	%option nounput
19
20	%{
21	// The lexer assumes the program has been preprocessed by cpp. Hence, all user level preprocessor directive have been
22	// performed and removed from the source. The only exceptions are preprocessor directives passed to the compiler (e.g.,
23	// line-number directives) and C/C++ style comments, which are ignored.
24
25	//************************** Includes and Defines **************************
26
27	unsigned int column = 0; // position of the end of the last token parsed
28	#define YY_USER_ACTION column += yyleng; // trigger before each matching rule's action
29
30	#include <string>
31	#include <cstdio> // FILENAME_MAX
32	using namespace std;
33
34	#include "ParseNode.h"
35	#include "TypedefTable.h"
36
37	char *yyfilename;
38	string *strtext; // accumulate parts of character and string constant value
39
40	#define RETURN_LOCN(x) yylval.tok.loc.file = yyfilename; yylval.tok.loc.line = yylineno; return( x )
41	#define RETURN_VAL(x) yylval.tok.str = new string( yytext ); RETURN_LOCN( x )
42	#define RETURN_CHAR(x) yylval.tok.str = nullptr; RETURN_LOCN( x )
43	#define RETURN_STR(x) yylval.tok.str = strtext; RETURN_LOCN( x )
44
45	#define WHITE_RETURN(x) // do nothing
46	#define NEWLINE_RETURN() column = 0; WHITE_RETURN( '\n' )
47	#define ASCIIOP_RETURN() RETURN_CHAR( (int)yytext[0] ) // single character operator
48	#define NAMEDOP_RETURN(x) RETURN_CHAR( x ) // multichar operator, with a name
49	#define NUMERIC_RETURN(x) rm_underscore(); RETURN_VAL( x ) // numeric constant
50	#define KEYWORD_RETURN(x) RETURN_CHAR( x ) // keyword
51	#define QKEYWORD_RETURN(x) typedefTable.isKind( yytext ); RETURN_VAL(x); // quasi-keyword
52	#define IDENTIFIER_RETURN() RETURN_VAL( typedefTable.isKind( yytext ) )
53	#define ATTRIBUTE_RETURN() RETURN_VAL( ATTR_IDENTIFIER )
54
55	void rm_underscore() {
56	// Remove underscores in numeric constant by copying the non-underscore characters to the front of the string.
57	yyleng = 0;
58	for ( int i = 0; yytext[i] != '\0'; i += 1 ) {
59	if ( yytext[i] == '`' ) {
60	// copy user suffix
61	for ( ; yytext[i] != '\0'; i += 1 ) {
62	yytext[yyleng] = yytext[i];
63	yyleng += 1;
64	} // for
65	break;
66	} // if
67	if ( yytext[i] != '_' ) {
68	yytext[yyleng] = yytext[i];
69	yyleng += 1;
70	} // if
71	} // for
72	yytext[yyleng] = '\0';
73	}
74
75	// Stop warning due to incorrectly generated flex code.
76	#pragma GCC diagnostic ignored "-Wsign-compare"
77	%}
78
79	octal [0-7]
80	nonzero [1-9]
81	decimal [0-9]
82	hex [0-9a-fA-F]
83	universal_char "\\"((u"_"?{hex_quad})\|(U"_"?{hex_quad}{2}))
84
85	// identifier, GCC: $ in identifier
86	identifier ([a-zA-Z_$]\|{universal_char})([0-9a-zA-Z_$]\|{universal_char})*
87
88	// attribute identifier, GCC: $ in identifier
89	attr_identifier "@"{identifier}
90
91	user_suffix_opt ("`"{identifier})?
92
93	// numeric constants, CFA: '_' in constant
94	hex_quad {hex}("_"?{hex}){3}
95	length ("ll"\|"LL"\|[lL])\|("hh"\|"HH"\|[hH])
96	integer_suffix_opt ("_"?(([uU]({length}?[iI]?)\|([iI]{length}))\|([iI]({length}?[uU]?)\|([uU]{length}))\|({length}([iI]?[uU]?)\|([uU][iI]))\|[zZ]))?{user_suffix_opt}
97
98	octal_digits ({octal})\|({octal}({octal}\|"_")*{octal})
99	octal_prefix "0""_"?
100	octal_constant (("0")\|({octal_prefix}{octal_digits})){integer_suffix_opt}
101
102	nonzero_digits ({nonzero})\|({nonzero}({decimal}\|"_")*{decimal})
103	decimal_constant {nonzero_digits}{integer_suffix_opt}
104
105	hex_digits ({hex})\|({hex}({hex}\|"_")*{hex})
106	hex_prefix "0"[xX]"_"?
107	hex_constant {hex_prefix}{hex_digits}{integer_suffix_opt}
108
109	// GCC: D (double) and iI (imaginary) suffixes, and DL (long double)
110	exponent "_"?[eE]"_"?[+-]?{decimal_digits}
111	floating_suffix ([fFdDlL]?[iI]?)\|([iI][lLfFdD])
112	floating_suffix_opt ("_"?({floating_suffix}\|"DL"))?{user_suffix_opt}
113	decimal_digits ({decimal})\|({decimal}({decimal}\|"_")*{decimal})
114	floating_decimal {decimal_digits}"."{exponent}?{floating_suffix_opt}
115	floating_fraction "."{decimal_digits}{exponent}?{floating_suffix_opt}
116	floating_constant ({decimal_digits}{exponent}{floating_suffix_opt})\|({decimal_digits}{floating_fraction})
117
118	binary_exponent "_"?[pP]"_"?[+-]?{decimal_digits}
119	hex_floating_suffix_opt ("_"?({floating_suffix}))?{user_suffix_opt}
120	hex_floating_fraction ({hex_digits}?"."{hex_digits})\|({hex_digits}".")
121	hex_floating_constant {hex_prefix}(({hex_floating_fraction}{binary_exponent})\|({hex_digits}{binary_exponent})){hex_floating_suffix_opt}
122
123	// character escape sequence, GCC: \e => esc character
124	simple_escape "\\"[abefnrtv'"?\\]
125	// ' stop editor highlighting
126	octal_escape "\\"{octal}("_"?{octal}){0,2}
127	hex_escape "\\""x""_"?{hex_digits}
128	escape_seq {simple_escape}\|{octal_escape}\|{hex_escape}\|{universal_char}
129	cwide_prefix "L"\|"U"\|"u"
130	swide_prefix {cwide_prefix}\|"u8"
131
132	// display/white-space characters
133	h_tab [\011]
134	form_feed [\014]
135	v_tab [\013]
136	c_return [\015]
137	h_white [ ]\|{h_tab}
138
139	// overloadable operators
140	op_unary_only "~"\|"!"
141	op_unary_binary "+"\|"-"\|"*"
142	op_unary_pre_post "++"\|"--"
143	op_unary {op_unary_only}\|{op_unary_binary}\|{op_unary_pre_post}
144
145	op_binary_only "/"\|"%"\|"\\"\|"^"\|"&"\|"\|"\|"<"\|">"\|"="\|"=="\|"!="\|"<<"\|">>"\|"<="\|">="\|"+="\|"-="\|"*="\|"/="\|"%="\|"\\="\|"&="\|"\|="\|"^="\|"<<="\|">>="
146	op_binary_over {op_unary_binary}\|{op_binary_only}
147	// op_binary_not_over "?"\|"->"\|"."\|"&&"\|"\|\|"\|"@="
148	// operator {op_unary_pre_post}\|{op_binary_over}\|{op_binary_not_over}
149
150	%x COMMENT
151	%x BKQUOTE
152	%x QUOTE
153	%x STRING
154
155	%%
156	/* line directives */
157	^{h_white}"#"{h_white}[0-9]+{h_white}["][^"\n]+["]."\n" {
158	/* " stop editor highlighting */
159	static char filename[FILENAME_MAX]; // temporarily store current source-file name
160	char *end_num;
161	char begin_string, end_string;
162	long lineno, length;
163	lineno = strtol( yytext + 1, &end_num, 0 );
164	begin_string = strchr( end_num, '"' );
165	if ( begin_string ) { // file name ?
166	end_string = strchr( begin_string + 1, '"' ); // look for ending delimiter
167	assert( end_string ); // closing quote ?
168	length = end_string - begin_string - 1; // file-name length without quotes or sentinel
169	assert( length < FILENAME_MAX ); // room for sentinel ?
170	memcpy( &filename, begin_string + 1, length ); // copy file name from yytext
171	filename[ length ] = '\0'; // terminate string with sentinel
172	//cout << "file " << filename << " line " << lineno << endl;
173	yylineno = lineno;
174	yyfilename = filename;
175	} // if
176	}
177
178	/* ignore preprocessor directives (for now) */
179	^{h_white}"#"[^\n]"\n" ;
180
181	/* ignore C style comments (ALSO HANDLED BY CPP) */
182	"/*" { BEGIN COMMENT; }
183	<COMMENT>.\|\n ;
184	<COMMENT>"*/" { BEGIN 0; }
185
186	/* ignore C++ style comments (ALSO HANDLED BY CPP) */
187	"//"[^\n]*"\n" ;
188
189	/* ignore whitespace */
190	{h_white}+ { WHITE_RETURN(' '); }
191	({v_tab}\|{c_return}\|{form_feed})+ { WHITE_RETURN(' '); }
192	({h_white}\|{v_tab}\|{c_return}\|{form_feed})*"\n" { NEWLINE_RETURN(); }
193
194	/* keywords */
195	_Alignas { KEYWORD_RETURN(ALIGNAS); } // C11
196	_Alignof { KEYWORD_RETURN(ALIGNOF); } // C11
197	__alignof { KEYWORD_RETURN(ALIGNOF); } // GCC
198	__alignof__ { KEYWORD_RETURN(ALIGNOF); } // GCC
199	asm { KEYWORD_RETURN(ASM); }
200	__asm { KEYWORD_RETURN(ASM); } // GCC
201	__asm__ { KEYWORD_RETURN(ASM); } // GCC
202	_At { KEYWORD_RETURN(AT); } // CFA
203	_Atomic { KEYWORD_RETURN(ATOMIC); } // C11
204	__attribute { KEYWORD_RETURN(ATTRIBUTE); } // GCC
205	__attribute__ { KEYWORD_RETURN(ATTRIBUTE); } // GCC
206	auto { KEYWORD_RETURN(AUTO); }
207	_Bool { KEYWORD_RETURN(BOOL); } // C99
208	break { KEYWORD_RETURN(BREAK); }
209	case { KEYWORD_RETURN(CASE); }
210	catch { KEYWORD_RETURN(CATCH); } // CFA
211	catchResume { KEYWORD_RETURN(CATCHRESUME); } // CFA
212	char { KEYWORD_RETURN(CHAR); }
213	choose { KEYWORD_RETURN(CHOOSE); } // CFA
214	_Complex { KEYWORD_RETURN(COMPLEX); } // C99
215	__complex { KEYWORD_RETURN(COMPLEX); } // GCC
216	__complex__ { KEYWORD_RETURN(COMPLEX); } // GCC
217	const { KEYWORD_RETURN(CONST); }
218	__const { KEYWORD_RETURN(CONST); } // GCC
219	__const__ { KEYWORD_RETURN(CONST); } // GCC
220	continue { KEYWORD_RETURN(CONTINUE); }
221	coroutine { KEYWORD_RETURN(COROUTINE); } // CFA
222	default { KEYWORD_RETURN(DEFAULT); }
223	disable { KEYWORD_RETURN(DISABLE); } // CFA
224	do { KEYWORD_RETURN(DO); }
225	double { KEYWORD_RETURN(DOUBLE); }
226	dtype { KEYWORD_RETURN(DTYPE); } // CFA
227	else { KEYWORD_RETURN(ELSE); }
228	enable { KEYWORD_RETURN(ENABLE); } // CFA
229	enum { KEYWORD_RETURN(ENUM); }
230	__extension__ { KEYWORD_RETURN(EXTENSION); } // GCC
231	extern { KEYWORD_RETURN(EXTERN); }
232	fallthrough { KEYWORD_RETURN(FALLTHRU); } // CFA
233	fallthru { KEYWORD_RETURN(FALLTHRU); } // CFA
234	finally { KEYWORD_RETURN(FINALLY); } // CFA
235	float { KEYWORD_RETURN(FLOAT); }
236	__float128 { KEYWORD_RETURN(FLOAT); } // GCC
237	for { KEYWORD_RETURN(FOR); }
238	forall { KEYWORD_RETURN(FORALL); } // CFA
239	fortran { KEYWORD_RETURN(FORTRAN); }
240	ftype { KEYWORD_RETURN(FTYPE); } // CFA
241	_Generic { KEYWORD_RETURN(GENERIC); } // C11
242	goto { KEYWORD_RETURN(GOTO); }
243	if { KEYWORD_RETURN(IF); }
244	_Imaginary { KEYWORD_RETURN(IMAGINARY); } // C99
245	__imag { KEYWORD_RETURN(IMAGINARY); } // GCC
246	__imag__ { KEYWORD_RETURN(IMAGINARY); } // GCC
247	inline { KEYWORD_RETURN(INLINE); } // C99
248	__inline { KEYWORD_RETURN(INLINE); } // GCC
249	__inline__ { KEYWORD_RETURN(INLINE); } // GCC
250	int { KEYWORD_RETURN(INT); }
251	__int128 { KEYWORD_RETURN(INT); } // GCC
252	__int128_t { KEYWORD_RETURN(INT); } // GCC
253	__label__ { KEYWORD_RETURN(LABEL); } // GCC
254	long { KEYWORD_RETURN(LONG); }
255	monitor { KEYWORD_RETURN(MONITOR); } // CFA
256	mutex { KEYWORD_RETURN(MUTEX); } // CFA
257	_Noreturn { KEYWORD_RETURN(NORETURN); } // C11
258	__builtin_offsetof { KEYWORD_RETURN(OFFSETOF); } // GCC
259	one_t { NUMERIC_RETURN(ONE_T); } // CFA
260	otype { KEYWORD_RETURN(OTYPE); } // CFA
261	register { KEYWORD_RETURN(REGISTER); }
262	restrict { KEYWORD_RETURN(RESTRICT); } // C99
263	__restrict { KEYWORD_RETURN(RESTRICT); } // GCC
264	__restrict__ { KEYWORD_RETURN(RESTRICT); } // GCC
265	return { KEYWORD_RETURN(RETURN); }
266	short { KEYWORD_RETURN(SHORT); }
267	signed { KEYWORD_RETURN(SIGNED); }
268	__signed { KEYWORD_RETURN(SIGNED); } // GCC
269	__signed__ { KEYWORD_RETURN(SIGNED); } // GCC
270	sizeof { KEYWORD_RETURN(SIZEOF); }
271	static { KEYWORD_RETURN(STATIC); }
272	_Static_assert { KEYWORD_RETURN(STATICASSERT); } // C11
273	struct { KEYWORD_RETURN(STRUCT); }
274	switch { KEYWORD_RETURN(SWITCH); }
275	thread { KEYWORD_RETURN(THREAD); } // C11
276	_Thread_local { KEYWORD_RETURN(THREADLOCAL); } // C11
277	throw { KEYWORD_RETURN(THROW); } // CFA
278	throwResume { KEYWORD_RETURN(THROWRESUME); } // CFA
279	timeout { QKEYWORD_RETURN(TIMEOUT); } // CFA
280	trait { KEYWORD_RETURN(TRAIT); } // CFA
281	try { KEYWORD_RETURN(TRY); } // CFA
282	ttype { KEYWORD_RETURN(TTYPE); } // CFA
283	typedef { KEYWORD_RETURN(TYPEDEF); }
284	typeof { KEYWORD_RETURN(TYPEOF); } // GCC
285	__typeof { KEYWORD_RETURN(TYPEOF); } // GCC
286	__typeof__ { KEYWORD_RETURN(TYPEOF); } // GCC
287	__uint128_t { KEYWORD_RETURN(INT); } // GCC
288	union { KEYWORD_RETURN(UNION); }
289	unsigned { KEYWORD_RETURN(UNSIGNED); }
290	__builtin_va_list { KEYWORD_RETURN(VALIST); } // GCC
291	virtual { KEYWORD_RETURN(VIRTUAL); } // CFA
292	void { KEYWORD_RETURN(VOID); }
293	volatile { KEYWORD_RETURN(VOLATILE); }
294	__volatile { KEYWORD_RETURN(VOLATILE); } // GCC
295	__volatile__ { KEYWORD_RETURN(VOLATILE); } // GCC
296	waitfor { KEYWORD_RETURN(WAITFOR); }
297	or { QKEYWORD_RETURN(WOR); } // CFA
298	when { KEYWORD_RETURN(WHEN); }
299	while { KEYWORD_RETURN(WHILE); }
300	with { KEYWORD_RETURN(WITH); } // CFA
301	zero_t { NUMERIC_RETURN(ZERO_T); } // CFA
302
303	/* identifier */
304	{identifier} { IDENTIFIER_RETURN(); }
305	{attr_identifier} { ATTRIBUTE_RETURN(); }
306	"`" { BEGIN BKQUOTE; }
307	<BKQUOTE>{identifier} { IDENTIFIER_RETURN(); }
308	<BKQUOTE>"`" { BEGIN 0; }
309
310	/* numeric constants */
311	{decimal_constant} { NUMERIC_RETURN(INTEGERconstant); }
312	{octal_constant} { NUMERIC_RETURN(INTEGERconstant); }
313	{hex_constant} { NUMERIC_RETURN(INTEGERconstant); }
314	{floating_decimal} { NUMERIC_RETURN(FLOATING_DECIMALconstant); } // must appear before floating_constant
315	{floating_fraction} { NUMERIC_RETURN(FLOATING_FRACTIONconstant); } // must appear before floating_constant
316	{floating_constant} { NUMERIC_RETURN(FLOATINGconstant); }
317	{hex_floating_constant} { NUMERIC_RETURN(FLOATINGconstant); }
318
319	/* character constant, allows empty value */
320	({cwide_prefix}[_]?)?['] { BEGIN QUOTE; rm_underscore(); strtext = new string( yytext, yyleng ); }
321	<QUOTE>[^'\\\n]* { strtext->append( yytext, yyleng ); }
322	<QUOTE>['\n]{user_suffix_opt} { BEGIN 0; strtext->append( yytext, yyleng ); RETURN_STR(CHARACTERconstant); }
323	/* ' stop editor highlighting */
324
325	/* string constant */
326	({swide_prefix}[_]?)?["] { BEGIN STRING; rm_underscore(); strtext = new string( yytext, yyleng ); }
327	<STRING>[^"\\\n]* { strtext->append( yytext, yyleng ); }
328	<STRING>["\n]{user_suffix_opt} { BEGIN 0; strtext->append( yytext, yyleng ); RETURN_STR(STRINGliteral); }
329	/* " stop editor highlighting */
330
331	/* common character/string constant */
332	<QUOTE,STRING>{escape_seq} { rm_underscore(); strtext->append( yytext, yyleng ); }
333	<QUOTE,STRING>"\\"{h_white}*"\n" {} // continuation (ALSO HANDLED BY CPP)
334	<QUOTE,STRING>"\\" { strtext->append( yytext, yyleng ); } // unknown escape character
335
336	/* punctuation */
337	"@" { ASCIIOP_RETURN(); }
338	"[" { ASCIIOP_RETURN(); }
339	"]" { ASCIIOP_RETURN(); }
340	"(" { ASCIIOP_RETURN(); }
341	")" { ASCIIOP_RETURN(); }
342	"{" { ASCIIOP_RETURN(); }
343	"}" { ASCIIOP_RETURN(); }
344	"," { ASCIIOP_RETURN(); } // also operator
345	":" { ASCIIOP_RETURN(); }
346	";" { ASCIIOP_RETURN(); }
347	"." { ASCIIOP_RETURN(); } // also operator
348	"..." { NAMEDOP_RETURN(ELLIPSIS); }
349
350	/* alternative C99 brackets, "<:" & "<:<:" handled by preprocessor */
351	"<:" { RETURN_VAL('['); }
352	":>" { RETURN_VAL(']'); }
353	"<%" { RETURN_VAL('{'); }
354	"%>" { RETURN_VAL('}'); }
355
356	/* operators */
357	"!" { ASCIIOP_RETURN(); }
358	"+" { ASCIIOP_RETURN(); }
359	"-" { ASCIIOP_RETURN(); }
360	"*" { ASCIIOP_RETURN(); }
361	"\\" { ASCIIOP_RETURN(); } // CFA, exponentiation
362	"/" { ASCIIOP_RETURN(); }
363	"%" { ASCIIOP_RETURN(); }
364	"^" { ASCIIOP_RETURN(); }
365	"~" { ASCIIOP_RETURN(); }
366	"&" { ASCIIOP_RETURN(); }
367	"\|" { ASCIIOP_RETURN(); }
368	"<" { ASCIIOP_RETURN(); }
369	">" { ASCIIOP_RETURN(); }
370	"=" { ASCIIOP_RETURN(); }
371	"?" { ASCIIOP_RETURN(); }
372
373	"++" { NAMEDOP_RETURN(ICR); }
374	"--" { NAMEDOP_RETURN(DECR); }
375	"==" { NAMEDOP_RETURN(EQ); }
376	"!=" { NAMEDOP_RETURN(NE); }
377	"<<" { NAMEDOP_RETURN(LS); }
378	">>" { NAMEDOP_RETURN(RS); }
379	"<=" { NAMEDOP_RETURN(LE); }
380	">=" { NAMEDOP_RETURN(GE); }
381	"&&" { NAMEDOP_RETURN(ANDAND); }
382	"\|\|" { NAMEDOP_RETURN(OROR); }
383	"->" { NAMEDOP_RETURN(ARROW); }
384	"+=" { NAMEDOP_RETURN(PLUSassign); }
385	"-=" { NAMEDOP_RETURN(MINUSassign); }
386	"\\=" { NAMEDOP_RETURN(EXPassign); } // CFA, exponentiation
387	"*=" { NAMEDOP_RETURN(MULTassign); }
388	"/=" { NAMEDOP_RETURN(DIVassign); }
389	"%=" { NAMEDOP_RETURN(MODassign); }
390	"&=" { NAMEDOP_RETURN(ANDassign); }
391	"\|=" { NAMEDOP_RETURN(ORassign); }
392	"^=" { NAMEDOP_RETURN(ERassign); }
393	"<<=" { NAMEDOP_RETURN(LSassign); }
394	">>=" { NAMEDOP_RETURN(RSassign); }
395
396	"@=" { NAMEDOP_RETURN(ATassign); } // CFA
397
398	/* CFA, operator identifier */
399	{op_unary}"?" { IDENTIFIER_RETURN(); } // unary
400	"?"({op_unary_pre_post}\|"()"\|"[?]"\|"{}") { IDENTIFIER_RETURN(); }
401	"^?{}" { IDENTIFIER_RETURN(); }
402	"?`"{identifier} { IDENTIFIER_RETURN(); } // unit operator
403	"?"{op_binary_over}"?" { IDENTIFIER_RETURN(); } // binary
404	/*
405	This rule handles ambiguous cases with operator identifiers, e.g., "int ??()", where the string "??" can be
406	lexed as "?"/"?" or ""/"??". Since it is common practise to put a unary operator juxtaposed to an identifier,
407	e.g., "*i", users will be annoyed if they cannot do this with respect to operator identifiers. Therefore, there is
408	a lexical look-ahead for the second case, with backtracking to return the leading unary operator and then
409	reparsing the trailing operator identifier. Otherwise a space is needed between the unary operator and operator
410	identifier to disambiguate this common case.
411
412	A similar issue occurs with the dereference, *?(...), and routine-call, ?()(...) identifiers. The ambiguity
413	occurs when the deference operator has no parameters, ?() and ?()(...), requiring arbitrary whitespace
414	look-ahead for the routine-call parameter-list to disambiguate. However, the dereference operator must have a
415	parameter/argument to dereference ?(...). Hence, always interpreting the string ?() as * ?() does not preclude
416	any meaningful program.
417
418	The remaining cases are with the increment/decrement operators and conditional expression:
419
420	i++? ...(...);
421	i?++ ...(...);
422
423	requiring arbitrary whitespace look-ahead for the operator parameter-list, even though that interpretation is an
424	incorrect expression (juxtaposed identifiers). Therefore, it is necessary to disambiguate these cases with a
425	space:
426
427	i++ ? i : 0;
428	i? ++i : 0;
429	*/
430	{op_unary}"?"({op_unary_pre_post}\|"()"\|"[?]"\|{op_binary_over}"?") {
431	// 1 or 2 character unary operator ?
432	int i = yytext[1] == '?' ? 1 : 2;
433	yyless( i ); // put back characters up to first '?'
434	if ( i > 1 ) {
435	NAMEDOP_RETURN( yytext[0] == '+' ? ICR : DECR );
436	} else {
437	ASCIIOP_RETURN();
438	} // if
439	}
440
441	/* unknown character */
442	. { yyerror( "unknown character" ); }
443
444	%%
445	// ----end of lexer----
446
447	void yyerror( const char * errmsg ) {
448	cout << (yyfilename ? yyfilename : "unknown file") << ':' << yylineno << ':' << column - yyleng + 1
449	<< ": " << SemanticError::error_str() << errmsg << " at token \"" << (yytext[0] == '\0' ? "EOF" : yytext) << '"' << endl;
450	}
451
452	// Local Variables: //
453	// mode: c++ //
454	// tab-width: 4 //
455	// compile-command: "make install" //
456	// End: //

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