ghc-7.0.4: The GHC API

SrcLoc

Contents

Description

This module contains types that relate to the positions of things in source files, and allow tagging of those things with locations

Synopsis

SrcLoc

data SrcLoc

Represents a single point within a file

Constructing SrcLoc

mkGeneralSrcLoc :: FastString -> SrcLoc

Creates a bad SrcLoc that has no detailed information about its location

generatedSrcLoc :: SrcLoc

Built-in bad SrcLoc values for particular locations

advanceSrcLoc :: SrcLoc -> Char -> SrcLoc

Move the SrcLoc down by one line if the character is a newline, to the next 8-char tabstop if it is a tab, and across by one character in any other case

Unsafely deconstructing SrcLoc

srcLocFile :: SrcLoc -> FastString

Gives the filename of the SrcLoc if it is available, otherwise returns a dummy value

srcLocLine :: SrcLoc -> Int

Raises an error when used on a bad SrcLoc

srcLocCol :: SrcLoc -> Int

Raises an error when used on a bad SrcLoc

Misc. operations on SrcLoc

pprDefnLoc :: SrcSpan -> SDoc

Pretty prints information about the SrcSpan in the style defined at ...

Predicates on SrcLoc

isGoodSrcLoc :: SrcLoc -> Bool

Good SrcLocs have precise information about their location

SrcSpan

data SrcSpan

A SrcSpan delimits a portion of a text file. It could be represented by a pair of (line,column) coordinates, but in fact we optimise slightly by using more compact representations for single-line and zero-length spans, both of which are quite common.

The end position is defined to be the column after the end of the span. That is, a span of (1,1)-(1,2) is one character long, and a span of (1,1)-(1,1) is zero characters long.

Constructing SrcSpan

mkGeneralSrcSpan :: FastString -> SrcSpan

Create a bad SrcSpan that has not location information

mkSrcSpan :: SrcLoc -> SrcLoc -> SrcSpan

Create a SrcSpan between two points in a file

wiredInSrcSpan :: SrcSpan

Built-in bad SrcSpans for common sources of location uncertainty

srcLocSpan :: SrcLoc -> SrcSpan

Create a SrcSpan corresponding to a single point

combineSrcSpans :: SrcSpan -> SrcSpan -> SrcSpan

Combines two SrcSpan into one that spans at least all the characters within both spans. Assumes the file part is the same in both inputs

Deconstructing SrcSpan

srcSpanStart :: SrcSpan -> SrcLoc

Returns the location at the start of the SrcSpan or a bad SrcSpan if that is unavailable

srcSpanEnd :: SrcSpan -> SrcLoc

Returns the location at the end of the SrcSpan or a bad SrcSpan if that is unavailable

srcSpanFileName_maybe :: SrcSpan -> Maybe FastString

Obtains the filename for a SrcSpan if it is good

Unsafely deconstructing SrcSpan

srcSpanStartLine :: SrcSpan -> Int

Raises an error when used on a bad SrcSpan

srcSpanEndLine :: SrcSpan -> Int

Raises an error when used on a bad SrcSpan

srcSpanStartCol :: SrcSpan -> Int

Raises an error when used on a bad SrcSpan

srcSpanEndCol :: SrcSpan -> Int

Raises an error when used on a bad SrcSpan

Predicates on SrcSpan

isGoodSrcSpan :: SrcSpan -> Bool

Test if a SrcSpan is good, i.e. has precise location information

isOneLineSpan :: SrcSpan -> Bool

True if the span is known to straddle only one line. For bad SrcSpan, it returns False

Located

data Located e

We attach SrcSpans to lots of things, so let's have a datatype for it.

Constructors

L SrcSpan e 

Instances

Constructing Located

noLoc :: e -> Located e

Deconstructing Located

unLoc :: Located e -> e

Combining and comparing Located values

eqLocated :: Eq a => Located a -> Located a -> Bool

Tests whether the two located things are equal

cmpLocated :: Ord a => Located a -> Located a -> Ordering

Tests the ordering of the two located things

addCLoc :: Located a -> Located b -> c -> Located c

Combine locations from two Located things and add them to a third thing

leftmost_largest :: SrcSpan -> SrcSpan -> Ordering

Alternative strategies for ordering SrcSpans

spans :: SrcSpan -> (Int, Int) -> Bool

Determines whether a span encloses a given line and column index

isSubspanOf

Arguments

:: SrcSpan

The span that may be enclosed by the other

-> SrcSpan

The span it may be enclosed by

-> Bool 

Determines whether a span is enclosed by another one