Haskell lambda function - parse error on input ‘)’

Question

I have the following code in Haskell and I want to change the line

toNanoStmt (VarDeclStmt _ array)= SeqList (toNanoStmt (map (\(VarDecl _ (Id a x) (Just exp))) array ))

Basically I want to use VarDeclStmt by creating a sequence of assign statements. A SeqList takes a list of statements. I have the list of VarDecls! And I have again use a map to convert the varDeclArr to a list of assignments. But am getting this error:

parse error on input ‘)’

Fyodor Soikin · Accepted Answer · 2022-05-11 12:17:39Z

2

Your lambda-expression has no body.

After parameters, there has to come a right arrow -> followed by the body, for example:

addTwo = (\x -> x + 2)

So in your case you need to do something like this:

toNanoStmt (VarDeclStmt _ array)= SeqList (toNanoStmt (map (\(VarDecl _ (Id a x) (Just exp)) -> <body goes here>) array ))

answered May 11, 2022 at 12:17

Fyodor Soikin

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1 Comment

Alexey Romanov Over a year ago

And the lambda probably should handle Nothing as well as Just exp.

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