string.match returns no value instead of nil when there is no match #543

• GopherLua is a Lua5.1 implementation. You should be familiar with Lua programming language. Have you read Lua 5.1 reference manual carefully?
• GopherLua is a Lua5.1 implementation. In Lua, to keep it simple, it is more important to remove functionalities rather than to add functionalities unlike other languages . If you are going to introduce some new cool functionalities into the GopherLua code base and the functionalities can be implemented by existing APIs, It should be implemented as a library.

1. What version of GopherLua are you using? : master (75f4976) and v1.1.1
2. What version of Go are you using? : 1.26.2
3. What operating system and processor architecture are you using? : darwin/arm64
4. What did you do? :

print(select("#", ("abc"):match("(%d+)")))
print(pcall(tonumber, ("abc"):match("(%d+)")))

5. What did you expect to see? : string.match returns nil when there is no match (Lua 5.1 manual: "If it finds one, then match returns the captures from the pattern; otherwise it returns nil"). Lua 5.1.5:

1
true	nil

6. What did you see instead? :

0
false	bad argument #1 to (anonymous) (value expected)

strMatch pushes LNil but returns 0, so no value is returned. Common code such as tonumber(s:match("(%d+)")) fails with "value expected".