R4d (Rad)

R4d is a text oriented macro prosessor made with rust.

R4d is in very early stage, so there might be lots of undetected bugs and changes will occur fast.

Currently only binary exists.

Usage

```bash

Usage : rad [OPTIONS] [FILE]...

Read from file and save to file

rad inputfile.txt -o outfile.txt

Read from file and print to stdout

rad input_file.txt

Read from standard input and print to file

printf '...text...' | rad -o out_file.txt

Read from stdin and print to stdout

printf '...text...' | rad

Use following options to decide error behaviours

default is stderr

rad -e FileToWriteError.txt # Log error to file rad -s # Suppress error ```

Type -h or --help to see full options.

Syntax

Macro definition

Definition syntax is similar to macro invocation but requires a specific form to sucessfully register the macro.

$define(name,arg1 arg2,$arg1() $arg2())

• First argument is a macro name. Macro should start with an alphabet character and following characters should be either alphanumeric or underscore.
• Second argument is macro's arguments. Macro argument also follows same rule of naming. Multiple arguments can be declared and should be separated by a whitespace.
• Third argument is a macro body. Any text can be included in the macro body while an unbalanced right parenthesis will end the definition. Enclose the body with double quote or escape with backslash to type literal parenthesis. Any character including newlines('\n', "\r\n") are all respected. (UTF-8)

You can simply bind the value to macro with =.

$define(v_name=Simon creek) which is technically same with $define(v_name,,Simon creek)

Macro inovokation

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 right parenthesis ends macro invocation and a non-double-quoted comma will change the number or content of arguments. If desirable content includes unbalanced right parentheses or commas, enclose the body with double quotes. Use escaped form of double quote, \" to use literal comma inside double quotes.

$define(order=first,second,third) $order() The result is first To include commas you need to enclose with double quotes $define(order="first,second,third") $order() converts to first,second,third

=> This behaviour might change in the future.

Advanced features

Literal input

``` $define(test,a,$a())

$test("This text prints as it is", but it should be only called on main level ))) )

"This text prints as it is", but it should be only called on main level ))) ```

Piping

``` $define(test,a,$a()) $test|(I'm going to be used by a pipe macro) $trim($repeat(2,$-()

))

I'm going to be used by a pipe macro I'm going to be used by a pipe macro ```

Goal

R4d aims to be a modern alternative to m4 processor, which means

• No trivial m4 quotes for macro definition
• Explicit rule for macro definition and usage so that de facto underscore rule is not necessary
• Easier binding with other programming languages(Rust's c binding)
• Enable combination of file stream and stdout
• As expressive as current m4 macro processor

Built-in macros (or macro-like functions)

Usages

Yet to come

Macros

• Tr (Translate)
• Substring
• Rust print! macro invocation
• Pause macro option (stop, recover pair)
• Write to temp file "/tmp %TEMP%"

Features

• Compiled rule file a.k.a. m4 frozen file