R4d is a text oriented macro prosessor made with rust.
R4d is in very early stage, so there might be lots of undetected bugs. Fast implementaiton was my priorites, thus optimization has had a least consideration for the time.
```bash
rad inputfile.txt -o outfile.txt
rad input_file.txt
printf '...text...' | rad -o out_file.txt
printf '...text...' | rad
rad -e FileToWriteError.txt # Log error to file rad -s # Suppress error rad -n # Always use unix newline (default is '\r\n' in windows platform) rad -p # Purge mode, print nothing if a macro doesn't exist rad -g # Always enable greedy for every macro invocation
rad test -f frozen.r4f
rad test -m frozen.r4f ```
Type -h or --help to see full options.
Definition syntax is similar to macro invocation but requires a specific form to sucessfully register the macro.
$define(name,arg1 arg2=$arg1() $arg2())
You can simply bind the value without giving arguments.
$define(v_name=Simon creek)
Definition's body can include any macro invocation in itself, thus wrong argument declaration cannot be detected at the time of definition. To make matters worse, arguments doesn't have any types either.
``` $define(panik,kalm=$calm()) $panik() $define(calm=KALM)
error: Failed to invoke a macro : "calm" --> stdin:2:2 $calm() KALM // After defnition it prints out without error ```
Thus, idiomatic way is to invoke a dummy after declartion to check if definition has sane invocations.
``` $define( test, aexpr apath = $bind+(cond,$eval($aexpr())) $bind+(truepath,$path(cache,$apath())) $bind+(falsepath,$path(cache,index.md)) $ifelse( $cond(), $include($truepath()), $include($falsepath()) ) ) $test|(1==1,out.md)
// Some outputs... ```
Prefix is a dollar sign($)
$define(macro_name,a1 a2=$a1() $a2())
$macro_name(arg1, arg2)
Macro can be invoked anywhere after the definition.
My name is $macro_name(Simon, Creek).
converts to
My name is Simon Creek.
Special argument $: is used for iterated value.
$foreach(\*John,Simon,Jane*\,Name : $:
)
$forloop(5,10,$:th
)
converts to
```
Name : John
Name : Simon
Name : Jane
5th 6th 7th 8th 9th 10th
```
NOTE
An unbalanced parenthesis changes the behaviour of macro invocation and a
non-double-quoted comma will change the number or content of arguments. If
desirable content includes unbalanced parentheses or commas, enclose the body
with string literal with the syntax of \* TEXT GOES HERE *\
``` $repeat(2,I'm,comma,separated
I'mI'm
To include commas you need to enclose with string literal
$repeat(2,*I'm,comma,separated*\
I'm,comma,separated I'm,comma,separated
```
Trim
Trim attribute trims preceding and following newlines, whitespaces from output. To make a definition look much more easier to read, many blank spaces are often included.
for e.g.
``` $define( test, aexpr apath = // This new line $bind+(cond,$eval($aexpr())) // Whitespaces before "$bind" $bind+(truepath,$path(cache,$apath())) // Whitespaces before "$bind" $bind+(falsepath,$path(cache,index.md)) // Whitespaces before "$bind" $ifelse( // Whitespaces before "$ifelse" $cond(), $include($truepath()), $include($falsepath()) ) // This new line )
1
2 3 4 5
```
Such definition is easier to read, but makes formatting unpredictable. So trim attribute comes handy, although you can always manually call trim macro.
``` ... $test^(1==1,out.md) // This is same with
1 2 3 4 5 ```
Greedy
Greedy attribute + parses arguments as greedy as possible so that last
argument will include or following characters in it. This is useful when
argument is a big chunk of data and includes multiple commas.
``` $define(test,a b c=$a() $b() $c()) $test(first, second, third, fourth, fifth, sixth)
first second third first second third, fourth, fifth, sixth ```
Piping
Pipe attribute | saves macro output into temporary value. This is useful
when you have to use mutlple macros for desired output which makes it hard to
grasp the code and maintain them.
``` $define(test,a=$a()) $test|(I'm going to be used by a pipe macro) $trim($repeat(2,$-() )) $test|(*I'll be requoted with literal*)
I'm going to be used by a pipe macro I'm going to be used by a pipe macro *I'll be requoted with literal*\ ```
Yield literal
Yield literal attribute * makes output printed as literal form. This is
useful when you have to give an argument literal value but you need to pre
process the data which means it cannot be marked as literal.
``` $define(array,content=$content()) $foreach($array*(a,b,c),Iterated: $:
Iterated: a Iterated: b Iterated: c
```
There are two types of errors. One is failed invocation error and second is invalid argument error. Failed invocation means that macro definition was not present at the time. On the other hand, invalid argument error is panic error since ignoring such error is very undesirable for end user experience..
``` $define(test=Test) $tesT()
error: Failed to invoke a macro : "tesT" --> test:2:2
$tesT() error: Invalid argument = File path : "typoinname/index.md" doesn't exist --> test:3:2 Processor panicked, exiting... ```
R4d aims to be a modern alternative to m4 processor, which means