CODEWITHSUNDEEP
lua
Beemo
Beemo

Reputation: 41

Why is this string not splitting in lua

So I am working on a project and I need to split a string that would look something like this:

if (x == 2){ output("Hello") }

This is my code:

local function splitIfStatement(str)
    local t = {}
    t[1] = ""
    t[2] = ""
    t[3] = ""
    local firstSplit = false
    local secondSplit = false
    local thirdSplit = false
    str:gsub(".", function(c)
        if c == "(" then
            firstSplit = true
        end
        if firstSplit == true then
            if c == "=" then
                firstSplit = false
                secondSplit = true
            else
                if c == "(" then
                else
                    t[1] = t[1] .. c
                end
            end
        end
        if secondSplit == true then
            if c == ")" then
                secondSplit = false
                thirdSplit = true
            else
                if c == "=" then
                else
                    t[2] = t[2] .. c
                end
            end
        end
    end)
    return t
end

I need to split the string at "(" so t[1] is only equal to "x" and t[2] is equal to 2 and then t[3] is equal to the "output()"

But when I run my code(note I haven't added the t[3]) t[1] returns: "x "Hello") }" and t[2] returns 2 like it should.

Anyways why isn't the split function working on the first split but it works on the second.

Thanks!

Upvotes: 2

Views: 52

Answers (2)

Nifim
Nifim

Reputation: 5031

In your loop you set firstSplit true if it hits a ( this happens in 2 places in your example, before x and right before "Hello"

you can fix this by setting firstSplit true and ignore the leading if ( before you beginning the loop. Then you allow the logic you have to handle the rest.

I also notice you dont have any logic that references t[3] right now.

That all said you really should use a pattern to parse something like this.

local function splitIfStatement(str)
    t = {str:match("if%s*%((%w+)%s*[=<>]+%s*(%d+)%)%s*{(.+)}")}
    return t
end

this pattern is very narrow and expects a specific type of if statement, you can learn more about lua patterns here: Understanding Lua Patterns

Upvotes: 2

lhf
lhf

Reputation: 72312

If the input is of the form

if (AAA == BBB){ CCC("Hello") }

with possible whitespace around the fields in question, then this code works:

S=[[if (x == 2){ output("Hello") } ]]
a,b,c = S:match('%(%s*(.-)%s.-%s+(.-)%)%s*{%s*(.-)%(')
print(a,b,c)

Upvotes: 1

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