Make sure the solution function is called right before return

Project.toml

@@ -1,14 +1,14 @@
 name = "ProblemSet"
 uuid = "806f51fd-16a3-4f55-bd44-f0d72f9cf926"
 authors = ["kagalenko-m-b <[email protected]> and contributors"]
-version = "0.7.9"
+version = "0.8"
 
 [deps]
 MacroTools = "1914dd2f-81c6-5fcd-8719-6d5c9610ff09"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [compat]
-MacroTools = "0.5.13"
+MacroTools = "0.5"
 julia = "1.9"
 
 [extras]

README.md

@@ -2,8 +2,8 @@
 
 [![Build Status](https://github.com/kagalenko-m-b/ProblemSet.jl/workflows/CI/badge.svg)](https://github.com/kagalenko-m-b/ProblemSet.jl/actions)
 
-The goal of this package is to facilitate the creation of problem assignments
-for a group of students. It allows to randomize the assignments in two ways:
+This package facilitates creation of  assignments for a group of students. It allows
+to randomize the assignments in two ways:
 
 * [random selection](Random_selection.md) of problems from a set, and
 

Random_selection.md

@@ -3,7 +3,7 @@
 A simplest set may be created by giving to the `@problemset` macro a list of questions
 as a multiline string:
 ```julia
-question_set = questions"""The first question.
+question_set = questions"The first question.
 The second question.
 ...
 The tenth question."

src/problem_compiler.jl

@@ -90,7 +90,8 @@ function process_body(mod, name, body)
     allunique(sol_vars) || @warn("duplicate variables at the left-hand "
                                  *"side of the tilde operator in @solution")
     problemdef[:sol_vars] = unique(sol_vars)
-    #
+    # Solution function should be called at the last line before return,
+    # rather than at the line where the @solution macro is found
     body_args = map(x->is_macro(x, :solution) ? :(:solution) : x, body_args)
     cond_body = Expr(body.head, body_args...)
     cond_vars = Symbol[]
@@ -138,16 +139,17 @@ function build_output(problemdef, linenumbernode)
     idx_solution = findfirst(x-> x == :(:solution), cond_args)
     # in place of @solution macro, insert into the problem's condition
     # call to the solution function
-    if isempty(problemdef[:sol_vars])
-        sol_expr = Expr(:call, problemdef[:name], problemdef[:cond_vars]...)
+    if isnothing(idx_solution)
+        sol_expr = nothing
     else
-        sol_expr = Expr(Symbol("="),  Expr(:tuple, problemdef[:sol_vars]...),
-                        Expr(:call, problemdef[:name], problemdef[:cond_vars]...))
-    end
-    if !isnothing(idx_solution)
-        cond_args[idx_solution] = sol_expr
-        cond_body.args = [linenumbernode; cond_body.args; return_expr]
+        if isempty(problemdef[:sol_vars])
+            sol_expr = Expr(:call, problemdef[:name], problemdef[:cond_vars]...)
+        else
+            sol_expr = Expr(Symbol("="),  Expr(:tuple, problemdef[:sol_vars]...),
+                            Expr(:call, problemdef[:name], problemdef[:cond_vars]...))
+        end
     end
+    cond_body.args = [linenumbernode; cond_body.args; sol_expr; return_expr]
     problemdef[:body] = cond_body
     ex_cond_function = MacroTools.combinedef(problemdef)
     #
@@ -207,10 +209,10 @@ end
 
 function macro_body(expr, name, n_args=1)
     is_macro(expr, name) || return nothing
-    args = filter(e -> !(e isa LineNumberNode), expr.args)
+    args = filter(e -> !((e isa LineNumberNode) || isnothing(e)), expr.args)
     if length(args) != n_args+1
         throw(ArgumentError("number of arguments of macro @$(string(name)) "*
-            "must be equal to $n_args, but is $(length(args))"))
+            "must be equal to $n_args, but is $(length(args) - 1)"))
     end
     args[end]
 end

test/runtests.jl

@@ -80,6 +80,7 @@ problem_set = :(@problemset test_problem_set begin
     @test pr.args[1] == Base.remove_linenums!(:(function sub_add(; )
                                                     z = rand(7:9)
                                                     w = rand(1:5)
+                                                    :solution
                                                     (zw_sub, zw_add) = sub_add(z, w)
                                                     return (;z, w, zw_sub, zw_add)
                                                 end)