define(name, body) documentation does not align with implementation

[voxik]

This line is incorrect IMHO:

rpm/docs/manual/lua.md

Line 120 in 689f1d8

#### define(name, body)

It should actually be something like define(name_body). This example actually seems to be correct:

rpm/docs/manual/lua.md

Line 128 in 689f1d8

rpm.define('foo 1')

But in any case, it would make more sense if the heading was correct and the define method supported the name and body arguments. Why it does not work like this?

[voxik]

IOW this is what the heading says:

$ rpm -E "%{lua:rpm.define('foo', '1')}" -E "%foo"
error: Macro %foo has empty body
error: lua script failed: [string "<lua>"]:1: error defining macro

but this is how it actually works:

$ rpm -E "%{lua:rpm.define('foo 1')}" -E "%foo"

1

[mlschroe]

It's kinda sad that this strips the leading spaces:

 rpm -E "%{lua:macros.define({'foo', ' 1 '})}" -E "x%{foo}x"

>1 <

[pmatilai]

Indeed, rpm.define() calls rpmDefineMacro() which is takes the macro name and the body as a single line - as you would get in a macro file. It doesn't make much sense as an API.

IIRC Lua's rpm.define() used that API because the other alternative lacked all the error checking back in the day, but things are quite different now, rpm.define() should just reroute to macros.define or something.

Note that this also works: macros['foo'] = 1

[voxik]

For the context, I have stumbled upon this issue playing with #2969 and my initial idea was to assign the whole macro body including the new lines to some macro with some specifically crafted name. But I was not able to achieve that no matter what and resorted to use variables (which is probably good enough variant).

It is my feeling that for whatever reason defining macro in Lua is limited comparing to plain .spec file, not being able to insert new line there. But maybe I have just not figured out the right amount of backslashes or what not.