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Contents
defmodule Graph do
defstruct attrs: [], nodes: [], edges: []
end
defmodule Dot do
# Normally matching on keywords is a bad idea as keyword lists can have
# several orders (i.e. `[a: 1, b: 2]` and `[b: 2, a: 1]`). But in this case
# only one keyword is allowed, so it's safe.
defmacro graph([do: ast]) do
g = do_graph(ast)
Macro.escape(
%Graph{attrs: Enum.sort(g.attrs),
nodes: Enum.sort(g.nodes),
edges: Enum.sort(g.edges)})
end
defp do_graph(nil) do
%Graph{}
end
defp do_graph({:__block__, _, stmts}) do
Enum.reduce(stmts, %Graph{}, &do_stmt/2)
end
defp do_graph(stmt) do
do_stmt(stmt, %Graph{})
end
defp do_stmt(stmt = {:graph, _, [kws]}, g) when is_list(kws) do
if Keyword.keyword?(kws) do
%{g | attrs: kws ++ g.attrs}
else
raise_invalid_stmt(stmt)
end
end
defp do_stmt({atom, _, nil}, g) when is_atom(atom) and atom != :-- do
%{g | nodes: [{atom, []} | g.nodes]}
end
defp do_stmt(stmt = {atom, _, [kws]}, g)
when is_atom(atom) and atom != :-- and is_list(kws) do
if Keyword.keyword?(kws) do
%{g | nodes: [{atom, kws} | g.nodes]}
else
raise_invalid_stmt(stmt)
end
end
defp do_stmt({:--, _, [{a, _, nil}, {b, _, nil}]}, g)
when is_atom(a) and is_atom(b) do
%{g | edges: [{a, b, []} | g.edges]}
end
defp do_stmt(stmt = {:--, _, [{a, _, nil}, {b, _, [kws]}]}, g)
when is_atom(a) and is_atom(b) and is_list(kws) do
if Keyword.keyword?(kws) do
%{g | edges: [{a, b, kws} | g.edges]}
else
raise_invalid_stmt(stmt)
end
end
defp do_stmt(stmt, _) do
raise_invalid_stmt(stmt)
end
defp raise_invalid_stmt(stmt) do
raise ArgumentError, message: "Invalid statement: #{inspect stmt}"
end
end
Version data entries
327 entries across 327 versions & 1 rubygems