F# Compiler Guide
QuickParse Module
Methods for cheaply and inaccurately parsing F#.
These methods are very old and are mostly to do with extracting "long identifier islands"
A.B.C
from F# source code, an approach taken from pre-F# VS samples for implementing intellisense.
This code should really no longer be needed since the language service has access to
parsed F# source code ASTs. However, the long identifiers are still passed back to GetDeclarations and friends in the
F# Compiler Service and it's annoyingly hard to remove their use completely.
In general it is unlikely much progress will be made by fixing this code - it will be better to
extract more information from the F# ASTs.
It's also surprising how hard even the job of getting long identifier islands can be. For example the code
below is inaccurate for long identifier chains involving ``...`` identifiers. And there are special cases
for active pattern names and so on.
Functions and values
| Function or value |
Description
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Full Usage:
CorrectIdentifierToken tokenText tokenTag
Parameters:
string
tokenTag : int
Returns: int
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Full Usage:
GetCompleteIdentifierIsland tolerateJustAfter lineStr index
Parameters:
bool
lineStr : string MaybeNull
index : int
Returns: (string * int * bool) option
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Given a string and a position in that string, find an identifier as expected by `GotoDefinition`. This will work when the cursor is immediately before the identifier, within the identifier, or immediately after the identifier. 'tolerateJustAfter' indicates that we tolerate being one character after the identifier, used for goto-definition In general, only identifiers composed from upper/lower letters and '.' are supported, but there are a couple of explicitly handled exceptions to allow some common scenarios: - When the name contains only letters and '|' symbol, it may be an active pattern, so we treat it as a valid identifier - e.g. let ( |Identity| ) a = a (but other identifiers that include '|' are not allowed - e.g. '||' operator) - It searches for double tick (``) to see if the identifier could be something like ``a b`` REVIEW: Also support, e.g., operators, performing the necessary mangling. (i.e., I would like that the name returned here can be passed as-is (post `.`-chopping) to `GetDeclarationLocation.) In addition, return the position where a `.` would go if we were making a call to `DeclItemsForNamesAtPosition` for intellisense. This will allow us to use find the correct qualified items rather than resorting to the more expensive and less accurate environment lookup.
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Full Usage:
GetPartialLongName (lineStr, index)
Parameters:
string MaybeNull
index : int
Returns: string list * string
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Get the partial long name of the identifier to the left of index.
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Full Usage:
GetPartialLongNameEx (lineStr, index)
Parameters:
string MaybeNull
index : int
Returns: PartialLongName
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Get the partial long name of the identifier to the left of index. For example, for `System.DateTime.Now` it returns PartialLongName ([|"System"; "DateTime"|], "Now", Some 32), where "32" pos of the last dot.
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Full Usage:
MagicalAdjustmentConstant
Returns: int
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Puts us after the last character.
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Full Usage:
TestMemberOrOverrideDeclaration tokens
Parameters:
FSharpTokenInfo[]
Returns: bool
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Tests whether the user is typing something like "member x." or "override (*comment*) x."
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