[GDBMS_cypher] e(), date() and localtime() functions

src/backend/utils/adt/cypher_funcs.c

@@ -37,7 +37,7 @@
 #include "utils/jsonb.h"
 #include "utils/memutils.h"
 #include "utils/typcache.h"
-#include <string.h>
+#include "utils/datetime.h"
 
 /* global variable - see postgres.c*/
 extern GraphWriteStats graphWriteStats;
@@ -1651,3 +1651,27 @@ tofloatornull(PG_FUNCTION_ARGS)
 	else
 		PG_RETURN_NULL();
 }
+
+Datum
+e(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_FLOAT8(2.718281828459045);
+}
+
+Datum
+date(PG_FUNCTION_ARGS)
+{
+	time_t t = time(NULL);
+	struct tm *tm = localtime(&t);
+	char s[11];
+	sprintf(s, "%04d-%02d-%02d", tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday);
+	PG_RETURN_TEXT_P(cstring_to_text(s));
+}
+
+Datum
+localtime_c(PG_FUNCTION_ARGS)
+{
+	time_t t = time(NULL);
+	struct tm *tm = localtime(&t);
+	PG_RETURN_TEXT_P(cstring_to_text(tm->tm_zone));
+}

src/include/catalog/pg_proc.dat

@@ -2195,6 +2195,9 @@
   proname => 'in_range', prorettype => 'bool',
   proargtypes => 'date date interval bool bool',
   prosrc => 'in_range_date_interval' },
+{ oid => '8008', descr => 'returns the current date in YYYY-MM-DD format',
+  proname => 'date', prorettype => 'text', pronargs => '0',
+  proargtypes => '', prosrc => 'date' },
 
 # OIDS 1100 - 1199
 
@@ -2246,6 +2249,9 @@
 { oid => '1145',
   proname => 'time_eq', proleakproof => 't', prorettype => 'bool',
   proargtypes => 'time time', prosrc => 'time_eq' },
+{ oid => '8009', descr => 'returns the local timezone',
+  proname => 'localtime_c', prorettype => 'text', pronargs => '0',
+  proargtypes => '', prosrc => 'localtime_c' },
 
 { oid => '1146',
   proname => 'circle_add_pt', prorettype => 'circle',
@@ -12050,4 +12056,9 @@
 { oid => '8005', descr => 'return float equivalents or null',
   proname => 'tofloatornull', prorettype => 'float8', proisstrict => 't', pronargs => '1',
   proargtypes => 'any', prosrc => 'tofloatornull' },
+
+# functions for returning constant values
+{ oid => '8007', descr => 'return the constant value of logarithmic base',
+  proname => 'e', prorettype => 'float8', pronargs => '0',
+  proargtypes => '', prosrc => 'e' },
 ]

src/include/utils/cypher_funcs.h

@@ -91,5 +91,8 @@ extern Datum get_last_graph_write_stats(PG_FUNCTION_ARGS);
 extern Datum tointeger(PG_FUNCTION_ARGS);
 extern Datum tofloat(PG_FUNCTION_ARGS);
 extern Datum tofloatornull(PG_FUNCTION_ARGS);
+extern Datum e(PG_FUNCTION_ARGS);
+extern Datum date(PG_FUNCTION_ARGS);
+extern Datum localtime_c(PG_FUNCTION_ARGS);
 
 #endif							/* CYPHER_FUNCS_H */

src/test/regress/expected/cypher_expr.out

@@ -828,6 +828,12 @@ MATCH (n:coll) RETURN n;
  coll[7.1]{"l": "graphdatabase", "u": "GRAPHDATABASE", "name": "GraphDatabase"}
 (1 row)
 
+RETURN e();
+         e         
+-------------------
+ 2.718281828459045
+(1 row)
+
 -- Text matching
 CREATE (:ts {v: 'a fat cat sat on a mat and ate a fat rat'::tsvector});
 MATCH (n:ts) WHERE n.v::tsvector @@ 'cat & rat'::tsquery RETURN n;

src/test/regress/expected/date.out

@@ -1495,3 +1495,15 @@ select make_time(10, 55, 100.1);
 ERROR:  time field value out of range: 10:55:100.1
 select make_time(24, 0, 2.1);
 ERROR:  time field value out of range: 24:00:2.1
+RETURN date() = (SELECT CAST(NOW() as date)) AS equality;
+ equality 
+----------
+ t
+(1 row)
+
+RETURN date() = (SELECT NOW()) AS equality;
+ equality 
+----------
+ f
+(1 row)
+

src/test/regress/sql/cypher_expr.sql

@@ -323,6 +323,8 @@ MATCH (n:coll) SET n.l = tolower(n.name);
 MATCH (n:coll) SET n.u = toupper(n.name);
 MATCH (n:coll) RETURN n;
 
+RETURN e();
+
 -- Text matching
 
 CREATE (:ts {v: 'a fat cat sat on a mat and ate a fat rat'::tsvector});

src/test/regress/sql/date.sql

@@ -364,3 +364,6 @@ select make_date(2013, 13, 1);
 select make_date(2013, 11, -1);
 select make_time(10, 55, 100.1);
 select make_time(24, 0, 2.1);
+
+RETURN date() = (SELECT CAST(NOW() as date)) AS equality;
+RETURN date() = (SELECT NOW()) AS equality;