[Harrison Pratt]

From the documentation, I expect openFileBOM/1 should behave the same as openFile8/1. However, when reading a simple text file with no byte-order marks successive readLine() statements return text and an empty string when the file is opened with openFileBOM/1.

Is this how openFileBOM/1 should behave?

Code: Select all

Output using openFileBOM(FN):
zero
 
one
 
two
 
three
 
Output using openFile8(FN):
zero
one
two
three

The output above is generated by this test code:

Code: Select all

    test() :-
        FN = @"SimpeTestFile.txt",
        In1 = inputStream_file::openFileBom(FN),
        stdio::write("\n\nOutput using openFileBOM(FN):"),
        In1:repeatToEndOfStream(),
        stdio::write("\n", In1:readLine()),
        In1:endOfStream(),
        In1:close(),
        In2 = inputStream_file::openFile8(FN),
        stdio::write("\n\nOutput using openFile8(FN):"),
        In2:repeatToEndOfStream(),
        stdio::write("\n", In2:readLine()),
        In2:endOfStream(),
        !,
        In2:close().
    test().

[Thomas Linder Puls]

I have not been able to reproduce this problem, can you attach the input file you use?
Which Visual Prolog version do you use for this.

(Also notice that repeatToEndOfStream works particularly well with foreach:

Code: Select all

clauses
    run() :-
        FN = @"..\test.txt",
        In1 = inputStream_file::openFileBom(FN),
        stdio::write("\n\nOutput using openFileBOM(FN):"),
        foreach In1:repeatToEndOfStream() do
            stdio::write("\n", In1:readLine())
        end foreach,
        In1:close(),
        In2 = inputStream_file::openFile8(FN),
        stdio::write("\n\nOutput using openFile8(FN):"),
        foreach In2:repeatToEndOfStream() do
            stdio::write("\n", In2:readLine())
        end foreach,
        In2:close().

)

[Harrison Pratt]

The test file I used is attached.

I am using VP 802.

[Thomas Linder Puls]

If I had used the correct version I would have reproduced it.

The openFileBom should look like this (last call is added):

Code: Select all

clauses
    openFileBom(Filename, Access) :-
        openFile(Filename, binary, Access),
        checkBom(),
        setCRLFconversion(true).

Alternative (to updating PFC) you can do the change in your own part of the code In1:setCRLFconversion(true):

Code: Select all

clauses
    run() :-
        FN = @"..\SimpeTestFile.txt",
        In1 = inputStream_file::openFileBom(FN),
        In1:setCRLFconversion(true),
        stdio::write("\n\nOutput using openFileBOM(FN):"),
        foreach In1:repeatToEndOfStream() do
            stdio::write("\n", In1:readLine())
        end foreach,
        In1:close(),
        In2 = inputStream_file::openFile8(FN),
        stdio::write("\n\nOutput using openFile8(FN):"),
        foreach In2:repeatToEndOfStream() do
            stdio::write("\n", In2:readLine())
        end foreach,
        In2:close().

[Harrison Pratt]

I understand -- and prefer option #2 rather than tweaking PFC code.

Question: what would happen if setCRLFconversion(true) was called in the 2nd clause of checkBOM/0 which is executed when there is no BOM?

Code: Select all

    checkBom() :-
        setPosition(0),
        setMode(stream::ansi(threadAnsi)),
        setCRLFconversion(true).  % <== why not here?

[Thomas Linder Puls]

CR LF conversion should be performed for any text file regardless of it contains a BOM or not.

[Harrison Pratt]

Silly question ... thanks.