Optionally pass an IO instead of filename to vtree saving

src/LoadSave/circuit_savers.jl

@@ -4,11 +4,15 @@ export save_as_dot, save_circuit, save_as_sdd, save_as_tex, save_as_dot2tex, sav
 # Save lines
 #####################
 
-function save_lines(name::String, lines::CircuitFormatLines)
-    open(name, "w") do f
-        for line in lines
-            println(f, line)
+function save_lines(file::Union{String, IO}, lines::CircuitFormatLines)
+    if file isa String
+        open(file, "w") do f
+            for line in lines
+                println(f, line)
+            end
         end
+    else
+        for line in lines println(file, line) end
     end
 end
 

src/LoadSave/vtree_loaders.jl

@@ -5,7 +5,7 @@ export load_vtree, zoo_vtree, zoo_vtree_file
 
 Load a vtree file from file. Currently only supports ".vtree" format.
 """
-function load_vtree(file::String, ::Type{V}=PlainVtree)::V where V<:Vtree
+function load_vtree(file::Union{String, IO}, ::Type{V}=PlainVtree)::V where V<:Vtree
     return compile_vtree_format_lines(parse_vtree_file(file), V)
 end
 
@@ -41,22 +41,22 @@ function parse_vtree_header_line(ln::String)
     VtreeHeaderLine()
 end
 
-function parse_vtree_file(file::String)::VtreeFormatLines
+function parse_vtree_file(file::Union{String, IO})::VtreeFormatLines
     q = Vector{VtreeFormatLine}()
-    open(file) do file
-        for ln in eachline(file)
-            if ln[1] == 'c'
-                push!(q, parse_vtree_comment_line(ln))
-            elseif ln[1] == 'L'
-                push!(q, parse_vtree_leaf_line(ln))
-            elseif ln[1] == 'I'
-                push!(q, parse_vtree_inner_line(ln))
-            elseif startswith(ln, "vtree")
-                push!(q, parse_vtree_header_line(ln))
-            else
-                error("Don't know how to parse vtree file format line $ln")
-            end
+    if file isa String file = open(file) end
+    for ln in eachline(file)
+        if ln[1] == 'c'
+            push!(q, parse_vtree_comment_line(ln))
+        elseif ln[1] == 'L'
+            push!(q, parse_vtree_leaf_line(ln))
+        elseif ln[1] == 'I'
+            push!(q, parse_vtree_inner_line(ln))
+        elseif startswith(ln, "vtree")
+            push!(q, parse_vtree_header_line(ln))
+        else
+            error("Don't know how to parse vtree file format line $ln")
         end
     end
+    close(file)
     q
-end
+end

src/LoadSave/vtree_savers.jl

@@ -50,16 +50,18 @@ Supported formats:
 * ".vtree" for Vtree files
 * ".dot" for dot files
 """
-function save_vtree(file::AbstractString, vtree::PlainVtree)
+function save_vtree(file::Union{AbstractString, IO}, vtree::PlainVtree)
 
     # 1. decide file type and open file
-    if endswith(file,".vtree")
-        f = VtreeConfigFile(file)
-    elseif endswith(file, ".dot")
-        f = VtreeDotFile(file)
-    else
-        throw("Unsupported file type. For example, for vtree format file name should end with .vtree")
-    end
+    if file isa AbstractString
+        if endswith(file,".vtree")
+            f = VtreeConfigFile(file)
+        elseif endswith(file, ".dot")
+            f = VtreeDotFile(file)
+        else
+            throw("Unsupported file type. For example, for vtree format file name should end with .vtree")
+        end
+    else f = (file = file,) end
 
     #2. map from PlainVtree to index for output
     index_cache = Dict{PlainVtree, UInt32}()
@@ -70,7 +72,7 @@ function save_vtree(file::AbstractString, vtree::PlainVtree)
         end
 
     #3. saving methods for header, nodes, tailer
-    function save_vtree_header(vtree::PlainVtree, f::VtreeConfigFile)
+    function save_vtree_header(vtree::PlainVtree, f::Union{VtreeConfigFile, NamedTuple})
         write(f.file, VTREE_FORMAT)
         write(f.file, "vtree $(num_nodes(vtree))\n")
     end
@@ -83,7 +85,7 @@ function save_vtree(file::AbstractString, vtree::PlainVtree)
         node_index = node2index(n)
         node_variable = n.var
 
-        if f isa VtreeConfigFile
+        if f isa VtreeConfigFile || f isa NamedTuple
             write(f.file, "L $node_index $node_variable\n")
         elseif f isa VtreeDotFile
             write(f.file, "$node_index [label=$(node_variable), shape=\"plaintext\"]\n")
@@ -97,7 +99,7 @@ function save_vtree(file::AbstractString, vtree::PlainVtree)
         left = node2index(n.left)
         right = node2index(n.right)
 
-        if f isa VtreeConfigFile
+        if f isa VtreeConfigFile || f isa NamedTuple
             write(f.file, "I $node_index $left $right\n")
         elseif f isa VtreeDotFile
             write(f.file, "$node_index -- $right\n")
@@ -107,7 +109,7 @@ function save_vtree(file::AbstractString, vtree::PlainVtree)
         end
     end
 
-    function save_vtree_footer(f::VtreeConfigFile)
+    function save_vtree_footer(f::Union{VtreeConfigFile, NamedTuple})
     end #do nothing
 
     function save_vtree_footer(f::VtreeDotFile)

test/LoadSave/vtree_parser_test.jl

@@ -33,16 +33,25 @@
         temp_path = "$tmp/little_4var_temp.vtree"
         save_vtree(temp_path, vtree)
 
-        # load it from file, and then run the same tests
-        vtree2 = load_vtree(temp_path)
-        test_vtree(vtree2)
-        @test vtree == vtree2 # we can test equality of plain vtrees!
+        # Save vtree from existing file stream
+        temp_stream = open("$tmp/little_4var_temp_stream.vtree", "w")
+        save_vtree(temp_stream, vtree)
+        close(temp_stream)
+
+        # load from file, and then run the same tests
+        temp_stream = open("$tmp/little_4var_temp_stream.vtree", "r")
+        for f in [temp_path, temp_stream]
+            vtree2 = load_vtree(f)
+            test_vtree(vtree2)
+            @test vtree == vtree2 # we can test equality of plain vtrees!
+        end
+        close(temp_stream)
 
         # Save dot file
         dot_path = "$tmp/little_4var_temp.dot"
         save_vtree(dot_path, vtree)
 
-        # Save unsupported format 
+        # Save unsupported format
         dot_path = "$tmp/little_4var_temp.bad_extension"
         @test_throws String save_vtree(dot_path, vtree)
     end