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Re: [Bug-apl] location of cursor on new apl session


From: enztec
Subject: Re: [Bug-apl] location of cursor on new apl session
Date: Mon, 30 Jan 2017 10:43:54 -0700

Hi,

In src/LineInput.cc   i changed 
allocated_height = 42;   and played with rows =    and even set   
allocated_height = 42000 and nothing changed??
putting in shortcut returns  also didn't do anything ?

you have some tight code there ;)

the problem also affects    
⍞←(⎕UCS 27), '[2J'
which should clear the screen and go to top of screen  but goes to the bottom 
of the screen like on startup

thanks





On Mon, 30 Jan 2017 11:37:22 +0100
Juergen Sauermann <address@hidden> wrote:

> Hi,
> 
> yes. but there is a reason for it. It is very difficult to figure, in a 
> portable way, at which line
> your cursor sits when entering some input. I tried with curses, but that did 
> not work well.
> The cursor position is needed when an input wraps around at the right end of 
> the screen
> (for backspacing over the wrapping point).
> 
> For this reason, he GNU APL model is that your input area are the last 
> allocated_height lines
> counting from the bottom of the screen. allocated_height is initially 1, but 
> increases
> when input lines are wrapping around.
> src/LineInput.cc
> If you move the input are up (as you wish) then line editing of inputs longer
> than the screen width stops working properly.
> 
> If you set the initial allocated_height to 24, then your input will start at 
> the top of the
> screen, but, trust me, this is asking for trouble.
> 
> /// Jürgen
> 
> 
> On 01/30/2017 03:37 AM, address@hidden wrote:
> Hi
> 
> I don't think
> LineEditContext::adjust_allocated_height()
> affects where the cursor is places after 'apl'
> i commented out tons of lines and nothing was effected
> 
> i'd like to have the cursor just indented when apl starts in an xterm and no 
> lines entered - i can see the cursor in the xterm right after apl starts but 
> then it moves to last line
> 
> 
> 
> 
> On Sat, 28 Jan 2017 18:53:38 +0100
> Juergen Sauermann <address@hidden> wrote:
> 
> Hi,
> 
> I suppose it is somewhere around LineEditContext::adjust_allocated_height().
> 
> I wrote my own readline() because the official one caused too many problems 
> on some platforms.
> 
> If I remember correctly then LineEditContext::adjust_allocated_height() makes 
> sure that there
> are enough empty lines at the bottom of the screen for entering some 
> (line-wrapped) multi-line input.
> 
> I am not sure what you are after - if it is only not clearing the screen then 
> you can change the
> CLEAR-EOS-SEQUENCE setting in your preferences file accordingly.
> 
> /// Jürgen
> 
> 
> On 01/28/2017 05:59 PM, address@hidden wrote:
> 
> with the banner disabled - i don't see apl clearing the xterm screen - if i 
> invoke apl after using 20 lines (in a 28 line xterm) then apl just starts at 
> the bottom of the screen - (8 lines below) - i have to clear the screen 
> (/usr/bin/clear) myself before invoking apl
> 
> when i start apl after 'i clear the screen' i can see the cursor at the top 
> of the xterm (while the apl loads) and then it moves to the bottom
> 
> Could you give me an idea if you have it on the top of your head where the 
> code for this is in your code...  i will try to find it myself in the 
> meantime :(  
> 
> (i've always been amazed at the complex code you have in your apl just so my 
> simple apl code will run)   </enztec wipes his brown nose>
> 
> 
> On Sat, 28 Jan 2017 12:57:49 +0100
> Juergen Sauermann <address@hidden> wrote:
> 
> Hi,
> 
> what you see is the intended behavior.
> 
> When you start GNU APL then the terminal is being reset (clear screen) so 
> that we can print the
> welcome banner. After that all user input is entered at the bottom of the 
> screen.
> 
> This is more portable than grabbing the input at the middle of the screen 
> because you can do it
> without ESCape sequences for cursor positioning. Everything is based on the 
> ASCII characters
> CR, LF, and Backspace, wehich are more portable than ESC sequences.
>  It also works better in scripts and pipes, eg. for web interfaces, and with 
> virtual terminals like xterm.
> 
> /// Jürgen
> 
> 
> On 01/27/2017 11:56 PM, address@hidden wrote:
> In all my previous apl installations the cursor in an xterm was at the top of 
> the xterm -  it stays there for 1.3  but with 1.6 and now 863  i can see it 
> start at the top when first opened but then goes to the bottom and indents - 
> any ideas?
> 
> I have 1.3 1.6 and 863 all installed on same computer
> 
> 
> 
> 
> 
> 
> 
> 
> 



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