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KcDan
Joined: 24 Jan 2006
Posts: 13
Location: Delaware
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 Posted: Thu Jan 26, 2006 12:57 pm Post subject: Evaluate function? |
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I'm working on a calculator for my shell and I cant find anywhere if there is a function that evaulates a string and turns it into a number, for example
"5+6-2" -> 9 |
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youresam
Joined: 06 Nov 2005
Posts: 87
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| Posted: Thu Jan 26, 2006 1:29 pm Post subject: |
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somenumber = tonumber("5+6-2")
then, somenumber should equal 9, I think. |
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KcDan
Joined: 24 Jan 2006
Posts: 13
Location: Delaware
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| Posted: Thu Jan 26, 2006 1:59 pm Post subject: |
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| I tried that earlier and it did not work, thanks though. |
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ema
Joined: 07 Dec 2005
Posts: 11
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| Posted: Fri Jan 27, 2006 12:17 am Post subject: |
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hi,
| Code: | expression = "5+6-2"
script = "return " .. expression -- convert to LUA script
func, err = loadstring(script)
if err then
-- syntax error
else
result = func() -- now result == 9
end
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will work. |
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KawaGeo
Joined: 27 Aug 2005
Posts: 191
Location: Calif Mountains
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| Posted: Fri Jan 27, 2006 3:06 am Post subject: |
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Also, the following will work:
| Code: | script = "return 5+6-2"
result = assert(loadstring(script))()
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Ref: Lua 5 Ref, page 40
Ema, you must have read PIL book well. :)
Hey, guys out there .. hint, hint
_________________
Geo Massar
Retired Engineer |
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KcDan
Joined: 24 Jan 2006
Posts: 13
Location: Delaware
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| Posted: Fri Jan 27, 2006 11:37 am Post subject: |
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| Thanks a lot you two. |
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