221 lines
5.5 KiB
Forth
Executable file
221 lines
5.5 KiB
Forth
Executable file
#!/usr/bin/env rre
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This will (hopefully) be a functional text editor written in RETRO.
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It draws influence from my earlier block editors, but is intended to
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operate on actual text files instead of blocks.
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First up, several variables and constants that are used through
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the rest of the code.
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~~~
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'SourceFile var
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'CurrentLine var
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'FID var
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~~~
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The configuration here is for two items. The number of lines from the
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file to show on screen, and the name of the temporary file to use
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when editing.
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~~~
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#80 'COLS const
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#12 'MAX-LINES const
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'/tmp/rre.edit 'TEMP-FILE s:const
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~~~
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Get the name of the file to edit. If no file is provided, exit.
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~~~
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sys:argc n:zero? [ #0 unix:exit ] if
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#0 sys:argv s:keep !SourceFile
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~~~
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This is just a shortcut to make writing strings to the current file
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easier.
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~~~
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:file:puts (s-) [ @FID file:write ] s:for-each ASCII:LF @FID file:write ;
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~~~
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I now turn my attention to displaying the file. I am aiming for
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an interface like:
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<filename> : <line-count>
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---------------------------------------------------------------
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* 99:
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100: :n:square dup * ;
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101:
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102: This is the current line
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103:
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---------------------------------------------------------------
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j: down | k: up | ... other helpful text ...
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The * denotes the currently selected line.
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I start with words to count the number of lines in the file and
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advance to the currently selected line.
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~~~
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:count-lines (-)
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#0 @SourceFile [ drop n:inc ] file:for-each-line ;
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:skip-to
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@CurrentLine #0 n:max [ @FID file:read-line drop ] times ;
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~~~
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Now for words to format the output. This should all be pretty clear in
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intent.
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`clear-display` uses an ANSI/VT100 escape sequence. This might need to
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be adjusted for your chosen terminal.
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~~~
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:clear-display (-)
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ASCII:ESC '%c[2J s:with-format puts nl ;
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~~~
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This just displays the separator bars.
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~~~
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:---- (-)
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COLS [ $- putc ] times nl ;
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~~~
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Next, a word to display the header. Currently just the name of the file
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being edited and the line count.
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~~~
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:header (-)
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count-lines @SourceFile '%s_:_%n_lines\n s:with-format puts ;
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~~~
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The `pad` word is used to make sure line numbers are all the same width.
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~~~
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:pad (n-n)
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dup #0 #9 n:between? [ '____ puts ] if
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dup #10 #99 n:between? [ '___ puts ] if
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dup #100 #999 n:between? [ '__ puts ] if
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dup #1000 #9999 n:between? [ '_ puts ] if ;
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~~~
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A line has a form:
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<indicator><number>: <text>
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The indicator is an asterisk, and visually marks the current line.
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~~~
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:mark-if-current (n-n)
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dup @CurrentLine eq? [ $* putc ] [ sp ] choose ;
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:line# (n-)
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putn ':_ puts ;
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:display-line (n-n)
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dup mark-if-current pad line# n:inc @FID file:read-line puts nl ;
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~~~
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~~~
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:display (-)
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@SourceFile file:R file:open !FID
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clear-display header ---- skip-to
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@CurrentLine count-lines MAX-LINES n:min [ display-line ] times drop
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---- dump-stack
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@FID file:close ;
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~~~
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With the code to display the file done, I can proceed on to words for
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handling editing. First, is a word to delete contents of the current
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line.
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The process here is to just write all but the current line to a dummy
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file, replacing the current line text with a newline. Then replace the
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original file with the dummy one.
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~~~
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:current? (n-nf)
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over @CurrentLine eq? ;
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:delete-line (-)
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TEMP-FILE file:W file:open !FID
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#0 @SourceFile [ current? [ drop s:empty ] if file:puts n:inc ] file:for-each-line drop
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@FID file:close
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@SourceFile TEMP-FILE 'mv_%s_%s s:with-format unix:system ;
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~~~
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~~~
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:kill-line (-)
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TEMP-FILE file:W file:open !FID
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#0 @SourceFile [ current? [ drop ] [ file:puts ] choose n:inc ] file:for-each-line drop
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@FID file:close
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@SourceFile TEMP-FILE 'mv_%s_%s s:with-format unix:system ;
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~~~
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~~~
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:add-line (-)
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TEMP-FILE file:W file:open !FID
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#0 @SourceFile [ current? [ ASCII:LF @FID file:write ] if file:puts n:inc ] file:for-each-line drop
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@FID file:close
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@SourceFile TEMP-FILE 'mv_%s_%s s:with-format unix:system ;
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~~~
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Replacing a line is next. Much like the `delete-line`, this writes all
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but the current line to a dummy file. It uses a `gets` word to read in
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the text to write instead of the original current line. When done, it
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replaces the original file with the dummy one.
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~~~
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:gets (-s)
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s:empty [ buffer:set
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[ repeat getc dup ASCII:LF -eq? 0; drop buffer:add again ] call drop ] sip ;
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:replace-line (-)
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TEMP-FILE file:W file:open !FID
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#0 @SourceFile [ current? [ drop gets ] if file:puts n:inc ] file:for-each-line drop
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@FID file:close
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@SourceFile TEMP-FILE 'mv_%s_%s s:with-format unix:system ;
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~~~
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~~~
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:goto (-)
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gets s:to-number !CurrentLine ;
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~~~
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And now tie everything together. There's a key handler and a top level loop.
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~~~
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:| '_|_ puts ;
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:describe (cs-)
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swap putc $: putc puts ;
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:help
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$1 'insert_line describe | $2 'replace_text describe | $3 '____________ describe |
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$4 'erase_text_ describe | $5 'delete_line_ describe nl
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$j 'down_______ describe | $k 'up__________ describe | $g 'goto_line___ describe |
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#32 '___________ describe | $q 'quit________ describe nl ;
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:handler
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getc
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$1 [ add-line ] case
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$2 [ replace-line ] case
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$4 [ delete-line ] case
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$5 [ kill-line ] case
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$j [ &CurrentLine v:inc &CurrentLine #0 #10000 v:limit ] case
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$k [ &CurrentLine v:dec &CurrentLine #0 #10000 v:limit ] case
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$g [ goto &CurrentLine #0 #10000 v:limit ] case
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$q [ 'stty_-cbreak unix:system #0 unix:exit ] case
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drop ;
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:edit
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'stty_cbreak unix:system
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repeat
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display help handler
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again ;
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~~~
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Run the editor.
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~~~
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edit
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~~~
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