Literate programming style macros in Literate.jl or Weave.jl

General Usage
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1

Dear All,

Is there any way of implementing “literate programming style macro” in Literate.jl or Weave.jl? My goal is to write a tutorial-style literate program in a logical order for the human reader. For example:

# Here is a complicated thing that we want to do. Given two numbers `a` and `b`, 
# we want to add them and store them in `c`.
    
<some_complicated_thing>=
c = a + b    

# But to do that, we first need to verify where a particular condition 
# on `a, b` holds.
        
<my_condition>=
a == 1 && b == 2

    
# Here is the function that does everything in one shot.
        
function complicated_function(a,b)

     if <my_condition>
          <some_complicated_thing>
     end

     return c

end

The function above should be the same as:

function complicated_function(a,b)

     if a == 1 && b == 2
         c = a + b  
     end
     
     return c

end

Is there a way of executing something similar in Literate.jl or Weave.jl? Any tips will be much appreciated!

2

I would not want to do this with macros.
this kind of literate program I assume comes from one of the original notions of literate programming by Knuth.
Knuth is also the creator of the most popular macro-centric programming language around: TeX.
TeX doesn’t have functions, only macros.
(though its macros are a bit safer looking than that…)
Here your code is bound up with variable names that have to match those that are used later.

I would write it with functions

# Here is a complicated thing that we want to do. Given two numbers `a` and `b`, 
# we want to add them
    
some_complicated_thing(a, b) = a + b    

# But to do that, we first need to verify where a particular condition 
# on `a, b` holds.
        
my_condition(a, b) = a == 1 && b == 2

    
# Here is the function that does everything in one shot.
        
function complicated_function(a,b)

     if my_condition(a, b)
          c = some_complicated_thing(a, b)
     end

     return c

end
1 Like
3

Thanks for your response, @oxinabox. The function-based method is a nice way of achieving similar behavior. Yes, <>= example indeed comes from original notions of literate programming by Knuth, I was wondering if one can also do the same thing in Literate.jl or Weave.jl as well, which are inspired by Knuth’s literate programming.

Thanks again!