Gene Selkov's SEG datatype (GiST example code)

contrib/seg/segscan.l

@@ -0,0 +1,53 @@
+%{
+/* 
+** A scanner for EMP-style numeric ranges 
+*/
+
+#include <string.h>
+#include <stdio.h>
+#include "segparse.h"
+#include "buffer.h"
+
+#define YY_NO_UNPUT 1
+#undef  yywrap
+
+/* flex screws a couple symbols when used with the -P otion; fix those */
+#define YY_DECL int seg_yylex YY_PROTO(( void )); \
+int seg_yylex YY_PROTO(( void ))
+#define yylval seg_yylval
+
+/* redefined YY_INPUT reads byte-wise from the memory area defined in buffer.c */
+#undef YY_INPUT
+#define YY_INPUT(buf,result,max_size) \
+{ \
+        int c = read_parse_buffer(); \
+        result = (c == '\0') ?  YY_NULL : (buf[0] = c, 1); \
+}
+
+void seg_flush_scanner_buffer(void); 
+%}
+
+range        (\.\.)(\.)?
+plumin       (\'\+\-\')|(\(\+\-)\)
+integer      [+-]?[0-9]+
+real         [+-]?[0-9]+\.[0-9]+
+float        ({integer}|{real})([eE]{integer})?
+
+%%
+
+{range}      yylval.text = yytext; return RANGE;
+{plumin}     yylval.text = yytext; return PLUMIN;
+{float}      yylval.text = yytext; return FLOAT;
+\<           yylval.text = "<"; return EXTENSION;
+\>           yylval.text = ">"; return EXTENSION;
+\~           yylval.text = "~"; return EXTENSION;
+[ ]+         /* discard spaces */
+.            return yytext[0]; /* alert parser of the garbage */
+
+%%
+
+int seg_yylex();
+
+void seg_flush_scanner_buffer(void) {
+  YY_FLUSH_BUFFER;
+}