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WANG Meng

13 Mar 2005 13 Mar '05

3:31 p.m.

Hi All, I am trying to use template haskell to splice top level declarations. However, GHC complains "<interactive>:1: Variable not in scope: `splice'" May I know what is the problem here? Did I use the wrong syntax? -W-M- @ @ | \_/

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Lemmih

13 Mar 13 Mar

4:54 p.m.

On Sun, 13 Mar 2005 23:31:28 +0800 (GMT-8), WANG Meng wrote:

Hi All,

I am trying to use template haskell to splice top level declarations. However, GHC complains "<interactive>:1: Variable not in scope: `splice'"

From http://www.haskell.org/ghc/docs/6.4/html/users_guide/template-haskell.html: 'Note that the syntax for a declaration splice uses "$" not "splice" as in the paper. Also the type of the enclosed expression must be Q [Dec], not [Q Dec] as in the paper.'

-- Friendly, Lemmih

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WANG Meng

5:38 p.m.

...
From http://www.haskell.org/ghc/docs/6.4/html/users_guide/template-haskell.html: 'Note that the syntax for a declaration splice uses "$" not "splice" as in the paper. Also the type of the enclosed expression must be Q [Dec], not [Q Dec] as in the paper.'

Thank you for your reply. I also tried to use "$". But GHC gives *Main> $(myparseDec "x=1") <interactive>:1: Couldn't match `Exp' against `Dec' Expected type: ExpQ Inferred type: Q Dec In the application `myparseDec "x=1"' In the definition of `it': it = $[splice](myparseDec "x=1") It seems "$" only takes in an "Q Exp". -W-M- @ @ | \_/ On Sun, 13 Mar 2005, Lemmih wrote:

On Sun, 13 Mar 2005 23:31:28 +0800 (GMT-8), WANG Meng wrote:

...
Hi All,

I am trying to use template haskell to splice top level declarations. However, GHC complains "<interactive>:1: Variable not in scope: `splice'"

-- Friendly, Lemmih

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Lemmih

5:46 p.m.

On Mon, 14 Mar 2005 01:38:25 +0800 (GMT-8), WANG Meng wrote:

...
...
From http://www.haskell.org/ghc/docs/6.4/html/users_guide/template-haskell.html: 'Note that the syntax for a declaration splice uses "$" not "splice" as in the paper. Also the type of the enclosed expression must be Q [Dec], not [Q Dec] as in the paper.'

Thank you for your reply. I also tried to use "$". But GHC gives

*Main> $(myparseDec "x=1")

<interactive>:1: Couldn't match `Exp' against `Dec' Expected type: ExpQ Inferred type: Q Dec In the application `myparseDec "x=1"' In the definition of `it': it = $[splice](myparseDec "x=1")

It seems "$" only takes in an "Q Exp".

You can't splice top level declarations from the interactive prompt. Save the code in a file and all will be well. (Notice that the TH code can't be in the module where the splicing takes place, and that your function should have the type 'Q [Dec]' instead of 'Q Dec'.) -- Friendly, Lemmih

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