Add warnings for unknown operators

Author: Schultzer

lib/adapters/ansi.ex

@@ -98,7 +98,7 @@ defmodule SQL.Adapters.ANSI do
   def token_to_string({:comma, _, value}, mod) do
     "#{mod.token_to_string(value)},"
   end
-  def token_to_string({tag, _, value}, _mod) when tag in ~w[ident numeric]a do
+  def token_to_string({tag, _, value}, _mod) when tag in ~w[ident numeric special]a do
     "#{value}"
   end
   def token_to_string(value, _mod) when is_atom(value) do
@@ -244,7 +244,7 @@ defmodule SQL.Adapters.ANSI do
   def to_iodata({:comma, _, value}, context, indent) do
     [context.module.to_iodata(value, context, indent), ?,, ?\s]
   end
-  def to_iodata({tag, _, value} = node, context, _indent) when tag in ~w[ident numeric]a do
+  def to_iodata({tag, _, value} = node, context, _indent) when tag in ~w[ident numeric special]a do
     case node in context.errors do
       true -> [:red, value, :reset]
       false -> value

lib/lexer.ex

@@ -130,7 +130,8 @@ defmodule SQL.Lexer do
   def lex(<<b, rest::binary>>, %{file: file}=context, line, column, acc) when b in ~c"!#$%&*+-/:<=>?@^|~" do
     case special(rest, [[]|[b]], column+1) do
       {rest, [_|_]=data, c} ->
-        lex(rest, context, line, c, [{:special, [type: :literal, line: line, column: column, end_column: c, file: file], data}|acc])
+        node = {:special, [type: :literal, line: line, column: column, end_column: c, file: file], data}
+        lex(rest, Map.update!(context, :errors, &:lists.append([[node],&1])), line, c, [node|acc])
       {rest, tag, c} ->
         lex(rest, context, line, c, [{tag, [type: :operator, line: line, column: column, end_column: c, file: file], []}|acc])
     end
@@ -247,6 +248,11 @@ defmodule SQL.Lexer do
  reserved = rules.keywords["<reserved word>"] ++ rules.keywords["<SQL/JSON key word>"]
  operators = Enum.uniq(Enum.flat_map(rules.operators, &elem(&1, 1)))
 
+  suggestions = Enum.map(operators, &to_string(elem(&1, 0)))
+  def suggest_operator(value) do
+      Enum.sort(Enum.filter(unquote(suggestions), &(String.jaro_distance("#{value}", &1) > 0)), &(String.jaro_distance(value, &1) >= String.jaro_distance(value, &2)))
+  end
+
   def ident(<<?', rest::binary>>, prefix, l, c) do
     {rest, data, l, c} = quote(rest, [], l, c+1)
     {rest, :quote, prefix, data, l, c}

lib/sql.ex

@@ -226,6 +226,9 @@ defmodule SQL do
 
   @doc false
   def format_error(errors), do: Enum.group_by(errors, &elem(&1, 2)) |> Enum.reduce([], fn
+    {k, [{:special, _, _}]}, acc -> [acc | ["the operator ", :red, k, :reset, " is invalid, did you mean any of #{Enum.join(SQL.Lexer.suggest_operator(:erlang.iolist_to_binary(k)), ", ")}", ?\n]]
+    {k, [{:special, _, _}|_]=v}, acc -> [acc | ["the operator ", :red, k, :reset, " is mentioned #{length(v)} times but is invalid, did you mean any of #{Enum.join(SQL.Lexer.suggest_operator(:erlang.iolist_to_binary(k)), ", ")}", ?\n]]
+    {k, [_]}, acc -> [acc | ["the relation ", :red, k, :reset, " does not exist", ?\n]]
     {k, v}, acc -> [acc | ["the relation ", :red, k, :reset, " is mentioned #{length(v)} times but does not exist", ?\n]]
   end)
 

test/sql_test.exs

@@ -105,7 +105,7 @@ defmodule SQLTest do
     end
 
     test "missing relation" do
-      assert capture_io(:stderr, fn -> SQL.parse("select id from users", set_sql_lock()) end) =~ "is mentioned 1 times but does not exist"
+      assert capture_io(:stderr, fn -> SQL.parse("select id from users", set_sql_lock()) end) =~ "does not exist"
     end
   end