In different Forths, how do I customize the interpreter?
For example, in SP-Forth the interpreter always write the stack content and always make a CR/LF before printing:
1 2 3
Ok ( 1 2 3 )
.s
1 2 3 Ok ( 1 2 3 )
I would like to see:
1 2 3 ok
.s 1 2 3 ok
And generally, I would like to be able to define new data inputs like
4-3i
{1,2,3,4,5}
The interpreter should then store the data as I defined in the extension. Also, on errors I would like soft stacks and variables to be reset.
Any ideas?
In different Forth systems there are different ways for customization.
In SP-Forth you can define another action for OK vector. For example, to avoid printing data stack state:
: OK2 ( -- ) STATE # IF EXIT THEN ." ok" CR ;
' OK2 TO OK
\ see the original definition in src/compiler/spf_translate.f
Though, it is difficult to avoid CRLF before "ok" in Windows console application since this CRLF is part of the text that you input.
Regarding a new data formats there is Recognizers RfD. It is implemented in some Forth systems, but not in SP-Forth yet.
In SP-Forth you can use NOTFOUND mechanism to add custom word format (words interpreter).
Related
I'm learning COBOL programming and using GNUCobol (on Linux) to compile and test some simple programs. In one of those programs I have found an unexpected behavior that I don't understand: when reading a sequential file of records, I'm always getting one extra record and, when writing these records to a report, the last record is duplicated.
I have made a very simple program to reproduce this behavior. In this case, I have a text file with a single line of text: "0123456789". The program should count the characters in the file (or 1 chararacter long records) and I expect it to display "10" as a result, but instead I get "11".
Also, when displaying the records, as they are read, I get the following output:
0
1
2
3
4
5
6
7
8
9
11
(There are two blank spaces between 9 and 11).
This is the relevant part of this program:
FD SIMPLE.
01 SIMPLE-RECORD.
05 SMP-NUMBER PIC 9(1).
[...]
PROCEDURE DIVISION.
000-COUNT-RECORDS.
OPEN INPUT SIMPLE.
PERFORM UNTIL SIMPLE-EOF
READ SIMPLE
AT END
SET SIMPLE-EOF TO TRUE
NOT AT END
DISPLAY SMP-NUMBER
ADD 1 TO RECORD-COUNT
END-READ
END-PERFORM
DISPLAY RECORD-COUNT.
CLOSE SIMPLE.
STOP RUN.
I'm using the default options for the compiler, and I have tried using 'WITH TEST {BEFORE|AFTER}' but the result is the same. What can be the cause of this behavior or how can I get the expected result?
Edit: I tried using an "empty" file as data source, expecting a 0 record count, using two different methods to empty the file:
$ echo "" > SIMPLE
This way the record count is 1 (ls -l gives a size of 1 byte for the file).
$ rm SIMPLE
$ touch SIMPLE
This way the record count is 0 (ls -l gives a size of 0 bytes for the file). So I guess that somehow the compiled program is detecting an extra character, but I don't know how to avoid this.
I found out that the cause of this behavior is the automatic newline character that vim seems to append when saving the data file.
After disabling this in vim this way
:set binary
:set noeol
the program works as expected.
Edit: A more elegant way to prevent this problem, when working with data files created from a text editor, is using ORGANIZATION IS LINE SEQUENTIAL in the SELECT clause.
Since the problem was caused by the data format, should I delete this question?
I'm toying with Rakudo Star 2015.09.
If I try to stringify an integer with a leading zero, the compiler issues a warning:
> say (~01234).WHAT
Potential difficulties:
Leading 0 does not indicate octal in Perl 6.
Please use 0o123 if you mean that.
at <unknown file>:1
------> say (~0123<HERE>).WHAT
(Str)
I thought maybe I could help the compiler by assigning the integer value to a variable, but obtained the same result:
> my $x = 01234; say (~$x).WHAT
Potential difficulties:
Leading 0 does not indicate octal in Perl 6.
Please use 0o1234 if you mean that.
at <unknown file>:1
------> my $x = 01234<HERE>; say (~$x).WHAT
(Str)
I know this is a silly example, but is this by design? If so, why?
And how can I suppress this kind of warning message?
Is there a reason you have data with leading zeroes? I tend to run into this problem when I have a column of postal codes.
When they were first thinking about Perl 6, one of the goals was to clean up some consistency issues. We had 0x and 0b (I think by that time), but Perl 5 still had to look for the leading 0 to guess it would be octal. See Radix Markers in Synopsis 2.
But, Perl 6 also has to care about what Perl 5 programmers are going to try to do and what they expect. Most people are going to expect a leading 0 to mean octal. But, it doesn't mean octal. It's that you typed the literal, not how you are using it. Perl 6 has lots of warnings about things that Perl 5 people would try to use, like foreach:
$ perl6 -e 'foreach #*ARGS -> $arg { say $arg }' 1 2 3
===SORRY!=== Error while compiling -e
Unsupported use of 'foreach'; in Perl 6 please use 'for' at -e:1
------> foreachâ #*ARGS -> $arg { say $arg }
To suppress that sort of warning, don't do what it's warning you about. The language doesn't want you to do that. If you need a string, start with a string '01234'. Or, if you want it to be octal, start with 0o. But, realize that stringifying a number will get you back the decimal representation:
$ perl6 -e 'say ~0o1234'
668
I understand that Julia has a complete set of low level tools for interfacing with binary files on one hand and some powerfull utilities such as readdlm to load text files containing rectangular data into Array structures on the other hand.
What I cannot discover in the standard library docs, however, is how to easily get input from less structured text files. In particular, what would be the Julia equivalent of the c++ idiom
some_input_stream >> a_variable_int_perhaps;
Given this is such a common usage scenario I am surprised something like this does not feature prominently in the standard library...
You can use readuntil http://docs.julialang.org/en/latest/stdlib/io-network/#Base.readuntil
shell> cat test.txt
1 2 3 4
julia> i,j = open("test.txt") do f
parse(Int, readuntil(f," ")), parse(Int, readuntil(f," "))
end
(1,2)
EDIT: To address comments
To get the last integer in an irregularly formatted ascii file you could use split if you know the character preceding the integer (I've use a blank space here)
shell> cat test.txt
1.0, two five:$#!() + 4
last line 3
julia> i = open("test.txt") do f
parse(Int, split(readline(f), " ")[end])
end
4
As far as code length is concerned, the above examples are completely self contained and the file is opened and closed in an exception safe manner (i.e. wrapped in a try-finally block). To do the same in C++ would be quite verbose.
I am relatively new to maxima. I want to know how to write an array into a text file using maxima.
I know it's late in the game for the original post, but I'll leave this here in case someone finds it in a search.
Let A be a Lisp array, Maxima array, matrix, list, or nested list. Then:
write_data (A, "some_file.data");
Let S be an ouput stream (created by openw or opena). Then:
write_data (A, S);
Entering ?? numericalio at the input prompt, or ?? write_ or ?? read_, will show some info about this function and related ones.
I've never used maxima (or even heard of it), but a little Google searching out of curiousity turned up this: http://arachnoid.com/maxima/files_functions.html
From what I can gather, you should be able to do something like this:
stringout("my_new_file.txt",values);
It says the second parameter to the stringout function can be one or more of these:
input: all user entries since the beginning of the session.
values: all user variable and array assignments.
functions: all user-defined functions (including functions defined within any loaded packages).
all: all of the above. Such a list is normally useful only for editing and extraction of useful sections.
So by passing values it should save your array assignments to file.
A bit more necroposting, as google leads here, but I haven't found it useful enough. I've needed to export it as following:
-0.8000,-0.8000,-0.2422,-0.242
-0.7942,-0.7942,-0.2387,-0.239
-0.7776,-0.7776,-0.2285,-0.228
-0.7514,-0.7514,-0.2124,-0.212
-0.7168,-0.7168,-0.1912,-0.191
-0.6750,-0.6750,-0.1655,-0.166
-0.6272,-0.6272,-0.1362,-0.136
-0.5746,-0.5746,-0.1039,-0.104
So I've found how to do this with printf:
with_stdout(filename, for i:1 thru length(z_points) do
printf (true,"~,4f,~,4f,~,4f,~,3f~%",bot_points[i],bot_points[i],top_points[i],top_points[i]));
A bit cleaner variation on the #ProdoElmit's answer:
list : [1,2,3,4,5]$
with_stdout("file.txt", apply(print, list))$
/* 1 2 3 4 5 is then what appears in file.txt */
Here the trick with apply is needed as you probably don't want to have square brackets in your output, as is produced by print(list).
For a matrix to be printed out, I would have done the following:
m : matrix([1,2],[3,4])$
with_stdout("file.txt", for row in args(m) do apply(print, row))$
/* 1 2
3 4
is what you then have in file.txt */
Note that in my solution the values are separated with spaces and the format of your values is fixed to that provided by print. Another caveat is that there is a limit on the number of function parameters: for example, for me (GCL 2.6.12) my method does not work if length(list) > 64.
I am using TeXnicCenter to edit a LaTeX document.
I now want to remove a certain tag (say, emph{blabla}} which occurs multiple times in my document , but not tag's content (so in this example, I want to remove all emphasization).
What is the easiest way to do so?
May also be using another program easily available on Windows 7.
Edit: In response to regex suggestions, it is important that it can deal with nested tags.
Edit 2: I really want to remove the tag from the text file, not just disable it.
Using a regular expression do something like s/\\emph\{([^\}]*)\}/\1/g. If you are not familiar with regular expressions this says:
s -- replace
/ -- begin match section
\\emph\{ -- match \emph{
( -- begin capture
[^\}]* -- match any characters except (meaning up until) a close brace because:
[] a group of characters
^ means not or "everything except"
\} -- the close brace
and * means 0 or more times
) -- end capture, because this is the first (in this case only) capture, it is number 1
\} -- match end brace
/ -- begin replace section
\1 -- replace with captured section number 1
/ -- end regular expression, begin extra flags
g -- global flag, meaning do this every time the match is found not just the first time
This is with Perl syntax, as that is what I am familiar with. The following perl "one-liners" will accomplish two tasks
perl -pe 's/\\emph\{([^\}]*)\}/\1/g' filename will "test" printing the file to the command line
perl -pi -e 's/\\emph\{([^\}]*)\}/\1/g' filename will change the file in place.
Similar commands may be available in your editor, but if not this will (should) work.
Crowley should have added this as an answer, but I will do that for him, if you replace all \emph{ with { you should be able to do this without disturbing the other content. It will still be in braces, but unless you have done some odd stuff it shouldn't matter.
The regex would be a simple s/\\emph\{/\{/g but the search and replace in your editor will do that one too.
Edit: Sorry, used the wrong brace in the regex, fixed now.
\renewcommand{\emph}[1]{#1}
any reasonably advanced editor should let you do a search/replace using regular expressions, replacing emph{bla} by bla etc.