Merge 933e0f4 into 45158fe

sisl · Oct 21, 2020 · df93b33 · df93b33
2 parents 45158fe + 933e0f4
commit df93b33
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Showing 2 changed files with 18 additions and 3 deletions.
diff --git a/src/ExprRules.jl b/src/ExprRules.jl
@@ -432,9 +432,13 @@ Generates a random RuleNode of return type typ and maximum depth max_depth.
 function Base.rand(::Type{RuleNode}, grammar::Grammar, typ::Symbol, max_depth::Int=10, 
     bin::Union{NodeRecycler,Nothing}=nothing)
     rules = grammar[typ]
-    rule_index = max_depth > 1 ?
-        StatsBase.sample(rules) :
-        StatsBase.sample(filter(r->isterminal(grammar,r), rules))
+
+    if max_depth <= 1
+        terminals = filter(r->isterminal(grammar,r), rules)
+        rule_index = !isempty(terminals) ? StatsBase.sample(terminals) : StatsBase.sample(rules)
+    else    
+        rule_index = StatsBase.sample(rules)
+    end
 
     rulenode = iseval(grammar, rule_index) ?
         RuleNode(bin, rule_index, Core.eval(grammar, rule_index)) :

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -427,3 +427,14 @@ let
     ex = get_executable(tree, grammar)
     interpret(tab, ex) == exp.([1, 2])
 end
+
+let
+    grammar = @grammar begin
+        A = B
+        B = C
+        C = D
+        D = E
+        E = 1
+    end
+    rulenode = rand(RuleNode, grammar, :A, 1)
+end