Pep and Nom

quotes in the ℕ𝕠𝕞 language

Both single and double quotes may be used in scripts and they have exactly the same role in the syntax of the nom language. But quoted text which starts with a double quote (") must end with a double quote, and the same rules applies to single quotes.

Quoted text can also span multiple lines.

use single or double quotes in pep/nom scripts

 r; '"' { add "<< single quote!\n"; print; } d;

If using the negation operator “!” in an “in-line” script, then enclose the whole thing in single quotes, so that the shell does not substitute the “!” character (or other special characters).

use single quotes in one-line ℙ𝕖𝕡 scripts to avoid bash substitution

 pep -e '![u-z],"/",";"{print;} clear;' -i "axbycz/;"

Prints: abc/;

The pep/nom language syntax allows quoted text to span more than one line. No special syntax is required and all special characters have the same meaning. This is mainly only useful as the argument to the “add” command, in order to improve the readability of scrips

A multi-line quoted text example



  begin { add '
    A multi-line 
    argument for "add".
    '; 
  } print; clear; quit;

It is not necessary to have any space between a command and any quoted argument. This is because the pep/nom language knows how to parse itself (see bumble.sf.net/books/pars/compile.pss for the amazing details). In fact, “white-space” (\n\t\s\r\f) is not really significant anywhere in a nom script - except within quotes.

no space is required before quotes



    read; add"."; # this is ok!
    replace"."".."; # this is be ok too.
    print;clear;
    # if the input is 'abc' this should print 'a..b..c..'

“ESCAPING” WITHIN QUOTES

The until command automatically recognises “escaped” quote characters, so it will not stop reading the input stream when it encounters \\" or \\'

using single quotes, and some abbreviated commands

 r; 'a' { add 'A'; print; } d;

Within quoted text, certain “escaped” characters have a special meaning. These characters have the same meaning in double and single quotes.

d/- \\n - represents a 'newline' character

\\r - a return character
\\f - a form feed (rarely used).
\\t - a tab

convert all tabs to 2 spaces in the input stream

 read; "\t" { clear; add "  "; } print; clear;

An abbreviated version of the above in-line pep/nom script

 r; "\t" { d; a "  "; } t;d;

create a "go" program, equivalent of the above script, compile and run



    pep -f tr/ ??translate.go.pss -i 'r;"\t"{d;a"  ";}t;d;' > notabs.go
    go build -o notabs notabs.go
    echo -e "no\ttabs\tplease!" | ?? notabs
    # should print 'no  tabs  please!'