[Newbies] Re: Re: reading lines from textfiles on Linux

[Charles D Hixson]

Klaus D. Witzel wrote:
> Hi Charles
>
> on Tue, 16 May 2006 03:55:10 +0200, you <charleshixsn at earthlink.net>
> wrote:
>
>> OK.  Now:
>> | fil lin n |
>> fil    :=    FileStream fileNamed: 'aising/data/technologies.csv' .
>> n    :=    0.
>> [fil atEnd] whileFalse:
>> [ lin := fil nextLine.
>>   n := n + 1.
>>   Transcript cr; show: 'lin '; show: n; show: ' = '; show: lin.
>> ].
>>  Transcript cr; show: 'normal end after '; show: n; show: ' lines'.
>
> You forgot to tell us
> a) SmalltalkImage current platformName
> b) fil lineEndConvention "after fil was opened"
> c) fil detectLineEndConvention "before the first nextLine"
>
> Note that detectLineEndConvention scans only the first (LookAheadCount
> = 2048) characters.
>
> /Klaus
>
>> results in:
>> normal end
>> lin 1 = 'technology'
>> 'id'    'name'    'cost1'    'cost2'    'cost3'    'pre1'    'pre2'
>> 'pre3'    'danger'    'typeName'    'typeValue'
>> 1    'Autonomous Vehicles'    40000    1000    0    27    16    0
>> 0        0
>> 2    'Sociology'    10    500    0    0    0    0    0
>> 'discover_public'    1000
>> 3    'Voice Synthesis'    8000    6000    0    32    0    0   
>> 0        0
>> 4    'Simulacra'    70000    90000    0    3    24    30    0        0
>> 5    ...
>> 'endgame_sing'    0
>> 39    'Hypnosis Field'    7000    5000    0    21    0    0   
>> 0        0
>> 40    'Quantum Computing'    30000    20000    0    11    0    0    0
>>     0
>> 41    'unknown'    1000000000    10000000000    0    41    0    0
>> 0        0
>>
>> normal end after 1 lines
>> Notice that the linefeeds aren't being taken as line separators.  They
>> are present, and affecting the formatting of the output, but nextLine is
>> grabbing the entire file.

OK, I've modified the code to include the detectLineEndConvention, thus: 

    | fil lin n |
    fil    :=    FileStream fileNamed: 'aising/data/technologies.csv' .
    fil    detectLineEndConvention.
    "fil defaultToLF."
    Transcript cr; show: 'LineEndConvention = '; show: fil
    lineEndConvention.
    fil  position: 0.
    n    :=    0.
    [fil atEnd] whileFalse:
    [ lin := fil nextLine.
      n := n + 1.
      Transcript cr; show: 'lin '; show: n; show: ' = '; show: lin.
    ].
     Transcript cr; show: 'normal end after '; show: n; show: ' lines'.

this causes the printout to begin:

    LineEndConvention = nil
    lin 1 = 'technology'                                       
    'id'    'name'    'cost1'    'cost2'    'cost3'    'pre1'   
    'pre2'    'pre3'    'danger'    'typeName'    'typeValue'
    1    'Autonomous Vehicles'    40000    1000    0    27    16    0   
    0        0
    ...
    normal end after 1 lines

as it did before.

Linux Squeak3.8-6665full.image
That's true, but it's a guess at what you're asking for, because I don't
understand the request for "SmalltalkImage current platformName ". 
Squeak-3.8-6665-i686-pc-linux-gnu-3.7.7.tar.gz is the file I started from.

The file lines end with an LF (i.e. 0x0a), as examined with a hex
editor.  Since all lines end with the same character, 2048 is plenty. 
(FWIW, the entire file is only  0x97B bytes long.  It's terminated by an
ordinary 0x0A, with no special markings.)

Also, I didn't "forget" to do fil detectLineEndConvention.  I didn't
know I was supposed to do it.  I'm still not sure, since it doesn't seem
to make any difference.  I do notice the difference with this method
however.  With a prior approach when I did position: 0 I got a
"primitive method throws an error" message, whereas with this the line
end convention is just set to nil.  Something is clearly wrong, as it
should be LF, but attempting to coerce it into LF just throws an error: 
Multi-byte stream does not understand method defaultToLF, which is
weird, as I can see that method in the class when I look.  I copied the
method name with a copy and paste from the MultiByteFileStream class
into the workspace, so I know I didn't misspell it.