#5910: Holes with other constraints
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Reporter: xnyhps | Owner:
Type: feature request | Status: new
Priority: normal | Milestone:
Component: Compiler (Type checker) | Version: 7.5
Keywords: holes | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: Other
Difficulty: Unknown | Testcase:
Blockedby: | Blocking:
Related: |
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Comment(by hamish):
How hard would it be to implement a -fdefer-undefined-errors that would
treat all undefined symbols as holes?
Then when you hit Ctrl+R to resolve them in Leksah we could include an
option to add the missing function to the module (currently it will only
add an import if the function is defined in a some other module). User
types...
{{{
main = putStrLn hello
}}}
Which results in a warning that hello is undefined. They then they hit
Ctrl+R and we would add...
{{{
hello :: String
hello = undefined
}}}
and select the word undefined in the above so they can start typing.
The problem with _? is we won't know when to include it until it is too
late. We could just add _? to whatever the user is typing, but for all we
know there could be a "hello" in scope and we might just be breaking valid
code. Also what if the user deletes an existing function we have no way
to know to add _? to the calling site to get a suitable type for the now
missing function.
If we need the type for autocomplete we will get it if the symbol is
undefined (because it will be treated as a hole). If it is defined we
probably don't want to autocomplete, but if the user presses Ctrl+Space we
can change "hello" to "hello_Leksah_Autocomplete" to get it.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5910#comment:19>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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