Update macros regex to support function calls as macro arguments (#64)

Author: dprokop

macros.go

@@ -128,7 +128,7 @@ func trimAll(s []string) []string {
 }
 
 func getMacroRegex(name string) string {
-	return fmt.Sprintf("\\$__%s\\b(?:\\((.*?)\\))?", name)
+	return fmt.Sprintf("\\$__%s\\b(?:\\((.*?\\)?)\\))?", name)
 }
 
 // Interpolate returns an interpolated query string given a backend.DataQuery

macros_test.go

@@ -60,8 +60,10 @@ func TestInterpolate(t *testing.T) {
 		{input: "select * from $__params(hello) AND $__params(world)", output: "select * from bar_hello AND bar_world", name: "same macro multiple times with different param"},
 		{input: "select * from $__params(world) AND $__foo() AND $__params(hello)", output: "select * from bar_world AND bar AND bar_hello", name: "different macros with different params"},
 		{input: "select * from foo where $__timeFilter(time)", output: "select * from foo where time >= '0001-01-01T00:00:00Z' AND time <= '0001-01-01T00:00:00Z'", name: "default timeFilter"},
+		{input: "select * from foo where $__timeFilter(cast(sth as timestamp))", output: "select * from foo where cast(sth as timestamp) >= '0001-01-01T00:00:00Z' AND cast(sth as timestamp) <= '0001-01-01T00:00:00Z'", name: "default timeFilter"},
 		{input: "select * from foo where $__timeTo(time)", output: "select * from foo where time <= '0001-01-01T00:00:00Z'", name: "default timeTo macro"},
 		{input: "select * from foo where $__timeFrom(time)", output: "select * from foo where time >= '0001-01-01T00:00:00Z'", name: "default timeFrom macro"},
+		{input: "select * from foo where $__timeFrom(cast(sth as timestamp))", output: "select * from foo where cast(sth as timestamp) >= '0001-01-01T00:00:00Z'", name: "default timeFrom macro"},
 		{input: "select * from foo where $__timeGroup(time,minute)", output: "select * from foo where grouped!", name: "overriden timeGroup macro"},
 		{input: "select $__column from $__table", output: "select my_col from my_table", name: "table and column macros"},
 	}
@@ -81,7 +83,7 @@ func TestInterpolate(t *testing.T) {
 }
 
 func TestGetMacroRegex_returns_composed_regular_expression(t *testing.T) {
-	assert.Equal(t, `\$__some_string\b(?:\((.*?)\))?`, getMacroRegex("some_string"))
+	assert.Equal(t, `\$__some_string\b(?:\((.*?\)?)\))?`, getMacroRegex("some_string"))
 }
 
 func TestGetMatches(t *testing.T) {