As Keith said, those 3 current\_* tokens are special. The scanner (lexical analyzer) recognizes them along with all the keywords (very efficiently by using a specialized hash table) and finally reduces them to a value, TK\_CTIME\_KW, which is all the parser directly sees. They become distinguished when the original (maybe case-folded) text is looked up in the same "table" that pragma\_function\_list shows. The grammar (in parse.y) requires that there be no parenthesis, just as Keith says the SQL standard specifies and the syntax diagram I linked documents. Because of this special processing for just those functions, there is no reason to be surprised that sqlite\_version() needs its parentheses. I think it was a mistake for the SQL standard to require this. Those 3 tokens act like literals in the language, but they are not constants like all other literals; they have more complex behavior such as we associate with functions. It might be considered syntactical sugar, but I think it's mainly an anomalous source of confusion such as you (and I) experienced.