Code Markdown to Bash
Introduction
A very, very simple transpiler from code-markdown to bash.
Transpile
# _containment_
## _fb pipeline_
script1
script2
script3
## _details_
### script1
echo hello
echo world
echo from script 1
### script2
echo hello
echo world
echo from script 2
### script3
echo hello
echo world
echo from script 3
to
#!/bin/bash
# _containment_
clear
set -e
trap 'catch' ERR
catch () {
echo '*** FATAL ERROR ***'
exit 1
}
# _details_
script1 () {
echo hello
echo world
echo from script 1
}
script2 () {
echo hello
echo world
echo from script 2
}
script3 () {
echo hello
echo world
echo from script 3
}
# _fb pipeline_
script1
script2
script3
Preamble
The preamble traps errors and prints a FATAL
```
clear
set -e
trap ‘catch’ ERR
catch () {
echo ‘** FATAL ERROR **’
exit 1
}
``
Any sub-script that exits with a non-0 exit code, will be caught by the above.
Why?
Layers - Important Stuff At The Top
We want to build software in layers.
We want the important stuff to be at the top of the script file, but, declaration-before-use requires that we define the details first and put the important stuff at the bottom of the script.
We want to use md-mode to elide details, so that we can look at the script in layers. We press TAB to expand layers only if we want to see the details.
We consider variables, traps, etc. to be at lower layers.
We want the transpiler to transpile our .md script into valid bash code.
This is an examplar - we show how to build a simple transpiler. We hope that the reader can build further transpilers that have more layers than what we show.
This is an examplar - we show some of the intermediate steps:
- Convert md to structured pseudo-code (braces) md2pseudo
- Convert the pseudo-code to bash-like code md 2 bash
- Insert swipl stuff (in a later essay).
Also, we show how easy it is to flip parsed code at will flip.
Emacs md-mode
Note that the above input syntax is editable by emacs md-mode.
Emacs md-mode provides the TAB key to allow eliding layers.
Usage and Testing
- Load md2bash.html into a browser.
- Scroll all the way down to the bottom and press
generate. - Copy the resulting code from the bottom textarea (“transpiled to bash”), and paste it into a file
test.bash. - chmod a+x test.bash
- ./test.bash