Move query to its own subpackage (#152)

Move all the query system to its own package. The reason is to
avoid it to rely on unexported methods and structures, and move
it out of the main package since this is really not a core
feature. It is still tied to the toml.TomlTree and toml.Position
structures for now.

* Move query mechanism to its own subpackage
* Rename QueryResult to Result to avoid stutter
* Add query.CompileAndExecute

Fixes #116

query/lexer_test.go

@@ -0,0 +1,179 @@
+package query
+
+import (
+	"testing"
+	"github.com/pelletier/go-toml"
+)
+
+func testQLFlow(t *testing.T, input string, expectedFlow []token) {
+	ch := lexQuery(input)
+	for idx, expected := range expectedFlow {
+		token := <-ch
+		if token != expected {
+			t.Log("While testing #", idx, ":", input)
+			t.Log("compared (got)", token, "to (expected)", expected)
+			t.Log("\tvalue:", token.val, "<->", expected.val)
+			t.Log("\tvalue as bytes:", []byte(token.val), "<->", []byte(expected.val))
+			t.Log("\ttype:", token.typ.String(), "<->", expected.typ.String())
+			t.Log("\tline:", token.Line, "<->", expected.Line)
+			t.Log("\tcolumn:", token.Col, "<->", expected.Col)
+			t.Log("compared", token, "to", expected)
+			t.FailNow()
+		}
+	}
+
+	tok, ok := <-ch
+	if ok {
+		t.Log("channel is not closed!")
+		t.Log(len(ch)+1, "tokens remaining:")
+
+		t.Log("token ->", tok)
+		for token := range ch {
+			t.Log("token ->", token)
+		}
+		t.FailNow()
+	}
+}
+
+func TestLexSpecialChars(t *testing.T) {
+	testQLFlow(t, " .$[]..()?*", []token{
+		{toml.Position{1, 2}, tokenDot, "."},
+		{toml.Position{1, 3}, tokenDollar, "$"},
+		{toml.Position{1, 4}, tokenLeftBracket, "["},
+		{toml.Position{1, 5}, tokenRightBracket, "]"},
+		{toml.Position{1, 6}, tokenDotDot, ".."},
+		{toml.Position{1, 8}, tokenLeftParen, "("},
+		{toml.Position{1, 9}, tokenRightParen, ")"},
+		{toml.Position{1, 10}, tokenQuestion, "?"},
+		{toml.Position{1, 11}, tokenStar, "*"},
+		{toml.Position{1, 12}, tokenEOF, ""},
+	})
+}
+
+func TestLexString(t *testing.T) {
+	testQLFlow(t, "'foo\n'", []token{
+		{toml.Position{1, 2}, tokenString, "foo\n"},
+		{toml.Position{2, 2}, tokenEOF, ""},
+	})
+}
+
+func TestLexDoubleString(t *testing.T) {
+	testQLFlow(t, `"bar"`, []token{
+		{toml.Position{1, 2}, tokenString, "bar"},
+		{toml.Position{1, 6}, tokenEOF, ""},
+	})
+}
+
+func TestLexStringEscapes(t *testing.T) {
+	testQLFlow(t, `"foo \" \' \b \f \/ \t \r \\ \u03A9 \U00012345 \n bar"`, []token{
+		{toml.Position{1, 2}, tokenString, "foo \" ' \b \f / \t \r \\ \u03A9 \U00012345 \n bar"},
+		{toml.Position{1, 55}, tokenEOF, ""},
+	})
+}
+
+func TestLexStringUnfinishedUnicode4(t *testing.T) {
+	testQLFlow(t, `"\u000"`, []token{
+		{toml.Position{1, 2}, tokenError, "unfinished unicode escape"},
+	})
+}
+
+func TestLexStringUnfinishedUnicode8(t *testing.T) {
+	testQLFlow(t, `"\U0000"`, []token{
+		{toml.Position{1, 2}, tokenError, "unfinished unicode escape"},
+	})
+}
+
+func TestLexStringInvalidEscape(t *testing.T) {
+	testQLFlow(t, `"\x"`, []token{
+		{toml.Position{1, 2}, tokenError, "invalid escape sequence: \\x"},
+	})
+}
+
+func TestLexStringUnfinished(t *testing.T) {
+	testQLFlow(t, `"bar`, []token{
+		{toml.Position{1, 2}, tokenError, "unclosed string"},
+	})
+}
+
+func TestLexKey(t *testing.T) {
+	testQLFlow(t, "foo", []token{
+		{toml.Position{1, 1}, tokenKey, "foo"},
+		{toml.Position{1, 4}, tokenEOF, ""},
+	})
+}
+
+func TestLexRecurse(t *testing.T) {
+	testQLFlow(t, "$..*", []token{
+		{toml.Position{1, 1}, tokenDollar, "$"},
+		{toml.Position{1, 2}, tokenDotDot, ".."},
+		{toml.Position{1, 4}, tokenStar, "*"},
+		{toml.Position{1, 5}, tokenEOF, ""},
+	})
+}
+
+func TestLexBracketKey(t *testing.T) {
+	testQLFlow(t, "$[foo]", []token{
+		{toml.Position{1, 1}, tokenDollar, "$"},
+		{toml.Position{1, 2}, tokenLeftBracket, "["},
+		{toml.Position{1, 3}, tokenKey, "foo"},
+		{toml.Position{1, 6}, tokenRightBracket, "]"},
+		{toml.Position{1, 7}, tokenEOF, ""},
+	})
+}
+
+func TestLexSpace(t *testing.T) {
+	testQLFlow(t, "foo bar baz", []token{
+		{toml.Position{1, 1}, tokenKey, "foo"},
+		{toml.Position{1, 5}, tokenKey, "bar"},
+		{toml.Position{1, 9}, tokenKey, "baz"},
+		{toml.Position{1, 12}, tokenEOF, ""},
+	})
+}
+
+func TestLexInteger(t *testing.T) {
+	testQLFlow(t, "100 +200 -300", []token{
+		{toml.Position{1, 1}, tokenInteger, "100"},
+		{toml.Position{1, 5}, tokenInteger, "+200"},
+		{toml.Position{1, 10}, tokenInteger, "-300"},
+		{toml.Position{1, 14}, tokenEOF, ""},
+	})
+}
+
+func TestLexFloat(t *testing.T) {
+	testQLFlow(t, "100.0 +200.0 -300.0", []token{
+		{toml.Position{1, 1}, tokenFloat, "100.0"},
+		{toml.Position{1, 7}, tokenFloat, "+200.0"},
+		{toml.Position{1, 14}, tokenFloat, "-300.0"},
+		{toml.Position{1, 20}, tokenEOF, ""},
+	})
+}
+
+func TestLexFloatWithMultipleDots(t *testing.T) {
+	testQLFlow(t, "4.2.", []token{
+		{toml.Position{1, 1}, tokenError, "cannot have two dots in one float"},
+	})
+}
+
+func TestLexFloatLeadingDot(t *testing.T) {
+	testQLFlow(t, "+.1", []token{
+		{toml.Position{1, 1}, tokenError, "cannot start float with a dot"},
+	})
+}
+
+func TestLexFloatWithTrailingDot(t *testing.T) {
+	testQLFlow(t, "42.", []token{
+		{toml.Position{1, 1}, tokenError, "float cannot end with a dot"},
+	})
+}
+
+func TestLexNumberWithoutDigit(t *testing.T) {
+	testQLFlow(t, "+", []token{
+		{toml.Position{1, 1}, tokenError, "no digit in that number"},
+	})
+}
+
+func TestLexUnknown(t *testing.T) {
+	testQLFlow(t, "^", []token{
+		{toml.Position{1, 1}, tokenError, "unexpected char: '94'"},
+	})
+}