Extracts info about the processed file to be later used by the header detection/manipulation functions.

Constructs new HeaderTemplate from provided data.

Adds given header at position specified by the HeaderInfo. Does nothing if any header is already present, use replaceHeader if you need to override it.

Drops header at position specified by the HeaderInfo from the given source code. Does nothing if no header is present.

Replaces existing header at position specified by the HeaderInfo in the given text. Basically combines addHeader with dropHeader. If no header is present, then the given one is added to the text.

Finds header position in given text, where position is represented by line number of first and last line of the header (numbered from zero). Based on the HeaderSyntax specified in given HeaderConfig, this function delegates its work to either findBlockHeader or findLineHeader.

>>> :set -XFlexibleContexts -XTypeFamilies -XQuasiQuotes
>>> import Headroom.Data.Regex (re)
>>> let hc = HeaderConfig ["hs"] 0 0 0 0 [] [] (BlockComment [re|^{-|] [re|(?<!#)-}$|] Nothing)
>>> findHeader hc $ SourceCode [(Code, "foo"), (Code, "bar"), (Comment, "{- HEADER -}")]
Just (2,2)

Finds header in the form of multi-line comment syntax, which is delimited with starting and ending pattern.

>>> :set -XQuasiQuotes
>>> import Headroom.Data.Regex (re)
>>> let sc = SourceCode [(Code, ""), (Comment, "{- HEADER -}"), (Code, ""), (Code,"")]
>>> findBlockHeader [re|^{-|] [re|(?<!#)-}$|] sc 0
Just (1,1)

Finds header in the form of single-line comment syntax, which is delimited with the prefix pattern.

>>> :set -XQuasiQuotes
>>> import Headroom.Data.Regex (re)
>>> let sc = SourceCode [(Code, ""), (Code, "a"), (Comment, "-- first"), (Comment, "-- second"), (Code, "foo")]
>>> findLineHeader [re|^--|] sc 0
Just (2,3)

Splits input source code into three parts:

1. all lines located before the very last occurence of one of the conditions from the first condition list
2. all lines between the first and last lists
3. all lines located after the very first occurence of one of the conditions from the second condition list

If both first and second patterns are empty, then all lines are returned in the middle part.

>>> :set -XQuasiQuotes
>>> import Headroom.Data.Regex (re)

>>> let ls = [(Code, "text"), (Code, "->"), (Code, "RESULT"), (Code, "<-"), (Code, "foo")]
>>> splitSource [[re|->|]] [[re|<-|]] $ SourceCode ls
(SourceCode [(Code,"text"),(Code,"->")],SourceCode [(Code,"RESULT")],SourceCode [(Code,"<-"),(Code,"foo")])

>>> let ls = [(Code, "text"), (Code, "->"), (Code, "RESULT"), (Code, "<-"), (Code, "foo")]
>>> splitSource [] [[re|<-|]] $ SourceCode ls
(SourceCode [],SourceCode [(Code,"text"),(Code,"->"),(Code,"RESULT")],SourceCode [(Code,"<-"),(Code,"foo")])

>>> splitSource [] [] $ SourceCode [(Code,"foo"), (Code,"bar")]
(SourceCode [],SourceCode [(Code,"foo"),(Code,"bar")],SourceCode [])