Merge pull request #350 from cucumber/cr-go2

cucumber-expressions: add go implementation

cucumber-expressions/go/Makefile

@@ -0,0 +1,19 @@
+SHELL := /usr/bin/env bash
+export GOPATH = $(realpath ./lib)
+
+default: test
+.PHONY: default
+
+# Use env variable ARGS to pass arguments to 'go test'
+#   (for running only a specific test or using verbose mode)
+#   Example: ARGS='-v -run TestCucumberExpression' make test
+test: lib/src/github.com/stretchr/testify
+	go test ${ARGS}
+.PHONY: clean
+
+lib/src/github.com/stretchr/testify:
+	go get github.com/stretchr/testify
+
+clean:
+	rm -rf lib/src lib/pkg
+.PHONY: clean

cucumber-expressions/go/argument.go

@@ -0,0 +1,43 @@
+package cucumberexpressions
+
+import "fmt"
+
+type Argument struct {
+	group         *Group
+	parameterType *ParameterType
+}
+
+func BuildArguments(treeRegexp *TreeRegexp, text string, parameterTypes []*ParameterType) []*Argument {
+	group := treeRegexp.Match(text)
+	if group == nil {
+		return nil
+	}
+	argGroups := group.Children()
+	if len(argGroups) != len(parameterTypes) {
+		panic(fmt.Errorf("%s has %d capture groups (%v), but there were %d parameter types (%v)", treeRegexp.Regexp().String(), len(argGroups), argGroups, len(parameterTypes), parameterTypes))
+	}
+	arguments := make([]*Argument, len(parameterTypes))
+	for i, parameterType := range parameterTypes {
+		arguments[i] = NewArgument(argGroups[i], parameterType)
+	}
+	return arguments
+}
+
+func NewArgument(group *Group, parameterType *ParameterType) *Argument {
+	return &Argument{
+		group:         group,
+		parameterType: parameterType,
+	}
+}
+
+func (a *Argument) Group() *Group {
+	return a.group
+}
+
+func (a *Argument) GetValue() interface{} {
+	return a.parameterType.Transform(a.group.Values())
+}
+
+func (a *Argument) ParameterType() *ParameterType {
+	return a.parameterType
+}

cucumber-expressions/go/combinatorial_generated_expression_factory.go

@@ -0,0 +1,48 @@
+package cucumberexpressions
+
+type CombinatorialGeneratedExpressionFactory struct {
+	expressionTemplate        string
+	parameterTypeCombinations [][]*ParameterType
+}
+
+func NewCombinatorialGeneratedExpressionFactory(expressionTemplate string, parameterTypeCombinations [][]*ParameterType) *CombinatorialGeneratedExpressionFactory {
+	return &CombinatorialGeneratedExpressionFactory{
+		expressionTemplate:        expressionTemplate,
+		parameterTypeCombinations: parameterTypeCombinations,
+	}
+}
+
+func (c *CombinatorialGeneratedExpressionFactory) GenerateExpressions() []*GeneratedExpression {
+	generatedExpressions := &GeneratedExpressionList{}
+	c.generatePermutations(generatedExpressions, 0, nil)
+	return generatedExpressions.ToArray()
+}
+
+func (c *CombinatorialGeneratedExpressionFactory) generatePermutations(generatedExpressions *GeneratedExpressionList, depth int, currentParameterTypes []*ParameterType) {
+	if depth == len(c.parameterTypeCombinations) {
+		generatedExpressions.Push(
+			NewGeneratedExpression(c.expressionTemplate, currentParameterTypes),
+		)
+		return
+	}
+
+	for _, parameterType := range c.parameterTypeCombinations[depth] {
+		c.generatePermutations(
+			generatedExpressions,
+			depth+1,
+			append(currentParameterTypes, parameterType),
+		)
+	}
+}
+
+type GeneratedExpressionList struct {
+	elements []*GeneratedExpression
+}
+
+func (g *GeneratedExpressionList) Push(expr *GeneratedExpression) {
+	g.elements = append(g.elements, expr)
+}
+
+func (g *GeneratedExpressionList) ToArray() []*GeneratedExpression {
+	return g.elements
+}

cucumber-expressions/go/combinatorial_generated_expression_factory_test.go

@@ -0,0 +1,76 @@
+package cucumberexpressions_test
+
+import (
+	"regexp"
+	"testing"
+
+	cucumberexpressions "."
+	"github.com/stretchr/testify/require"
+)
+
+func TestCombinatorialGeneratedExpressionFactory(t *testing.T) {
+	t.Run("generates multiple expressions", func(t *testing.T) {
+		colorParameterType, err := cucumberexpressions.NewParameterType(
+			"color",
+			[]*regexp.Regexp{regexp.MustCompile("red|blue|yellow")},
+			"",
+			func(arg3 ...string) interface{} { return arg3[0] },
+			false,
+			true,
+		)
+		require.NoError(t, err)
+		csscolorParameterType, err := cucumberexpressions.NewParameterType(
+			"csscolor",
+			[]*regexp.Regexp{regexp.MustCompile("red|blue|yellow")},
+			"",
+			func(arg3 ...string) interface{} { return arg3[0] },
+			false,
+			true,
+		)
+		require.NoError(t, err)
+		dateParameterType, err := cucumberexpressions.NewParameterType(
+			"date",
+			[]*regexp.Regexp{regexp.MustCompile(`\d{4}-\d{2}-\d{2}`)},
+			"",
+			func(arg3 ...string) interface{} { return arg3[0] },
+			false,
+			true,
+		)
+		require.NoError(t, err)
+		datetimeParameterType, err := cucumberexpressions.NewParameterType(
+			"datetime",
+			[]*regexp.Regexp{regexp.MustCompile(`\d{4}-\d{2}-\d{2}`)},
+			"",
+			func(arg3 ...string) interface{} { return arg3[0] },
+			false,
+			true,
+		)
+		require.NoError(t, err)
+		timestampParameterType, err := cucumberexpressions.NewParameterType(
+			"timestamp",
+			[]*regexp.Regexp{regexp.MustCompile(`\d{4}-\d{2}-\d{2}`)},
+			"",
+			func(arg3 ...string) interface{} { return arg3[0] },
+			false,
+			true,
+		)
+		require.NoError(t, err)
+		parameterTypeCombinations := [][]*cucumberexpressions.ParameterType{
+			{colorParameterType, csscolorParameterType},
+			{dateParameterType, datetimeParameterType, timestampParameterType},
+		}
+		factory := cucumberexpressions.NewCombinatorialGeneratedExpressionFactory("I bought a {%s} ball on {%s}", parameterTypeCombinations)
+		var expressions []string
+		for _, g := range factory.GenerateExpressions() {
+			expressions = append(expressions, g.Source())
+		}
+		require.Equal(t, expressions, []string{
+			"I bought a {color} ball on {date}",
+			"I bought a {color} ball on {datetime}",
+			"I bought a {color} ball on {timestamp}",
+			"I bought a {csscolor} ball on {date}",
+			"I bought a {csscolor} ball on {datetime}",
+			"I bought a {csscolor} ball on {timestamp}",
+		})
+	})
+}

cucumber-expressions/go/cucumber_expression.go

@@ -0,0 +1,98 @@
+package cucumberexpressions
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+var ESCAPE_REGEXP = regexp.MustCompile(`([\\^[$.|?*+])`)
+var PARAMETER_REGEXP = regexp.MustCompile(`(\\\\\\\\)?{([^}]+)}`)
+var OPTIONAL_REGEXP = regexp.MustCompile(`(\\\\\\\\)?\([^)]+\)`)
+var ALTERNATIVE_NON_WHITESPACE_TEXT_REGEXP = regexp.MustCompile(`([^\s^/]+)((\/[^\s^/]+)+)`)
+var DOUBLE_ESCAPE = `\\\\`
+
+type CucumberExpression struct {
+	source         string
+	parameterTypes []*ParameterType
+	treeRegexp     *TreeRegexp
+}
+
+func NewCucumberExpression(expression string, parameterTypeRegistry *ParameterTypeRegistry) (*CucumberExpression, error) {
+	result := &CucumberExpression{source: expression}
+
+	expression = result.processEscapes(expression)
+	expression = result.processOptional(expression)
+	expression = result.processAlteration(expression)
+	expression, err := result.processParameters(expression, parameterTypeRegistry)
+	if err != nil {
+		return nil, err
+	}
+	expression = "^" + expression + "$"
+
+	result.treeRegexp = NewTreeRegexp(regexp.MustCompile(expression))
+	return result, nil
+}
+
+func (c *CucumberExpression) Match(text string) ([]*Argument, error) {
+	return BuildArguments(c.treeRegexp, text, c.parameterTypes), nil
+}
+
+func (c *CucumberExpression) Regexp() *regexp.Regexp {
+	return c.treeRegexp.Regexp()
+}
+
+func (c *CucumberExpression) Source() string {
+	return c.source
+}
+
+func (c *CucumberExpression) processEscapes(expression string) string {
+	return ESCAPE_REGEXP.ReplaceAllString(expression, `\$1`)
+}
+
+func (c *CucumberExpression) processOptional(expression string) string {
+	return OPTIONAL_REGEXP.ReplaceAllStringFunc(expression, func(match string) string {
+		if strings.HasPrefix(match, DOUBLE_ESCAPE) {
+			return fmt.Sprintf(`\(%s\)`, match[5:len(match)-1])
+		}
+		return fmt.Sprintf("(?:%s)?", match[1:len(match)-1])
+	})
+}
+
+func (c *CucumberExpression) processAlteration(expression string) string {
+	return ALTERNATIVE_NON_WHITESPACE_TEXT_REGEXP.ReplaceAllStringFunc(expression, func(match string) string {
+		return fmt.Sprintf("(?:%s)", strings.Replace(match, "/", "|", -1))
+	})
+}
+
+func (c *CucumberExpression) processParameters(expression string, parameterTypeRegistry *ParameterTypeRegistry) (string, error) {
+	var err error
+	result := PARAMETER_REGEXP.ReplaceAllStringFunc(expression, func(match string) string {
+		if strings.HasPrefix(match, DOUBLE_ESCAPE) {
+			return fmt.Sprintf(`\{%s\}`, match[5:len(match)-1])
+		}
+
+		typeName := match[1 : len(match)-1]
+		parameterType := parameterTypeRegistry.LookupByTypeName(typeName)
+		if parameterType == nil {
+			err = NewUndefinedParameterTypeError(typeName)
+			return match
+		}
+		c.parameterTypes = append(c.parameterTypes, parameterType)
+		return buildCaptureRegexp(parameterType.regexps)
+	})
+	return result, err
+}
+
+func buildCaptureRegexp(regexps []*regexp.Regexp) string {
+	if len(regexps) == 1 {
+		return fmt.Sprintf("(%s)", regexps[0].String())
+	}
+
+	captureGroups := make([]string, len(regexps))
+	for i, r := range regexps {
+		captureGroups[i] = fmt.Sprintf("(?:%s)", r.String())
+	}
+
+	return fmt.Sprintf("(%s)", strings.Join(captureGroups, "|"))
+}

cucumber-expressions/go/cucumber_expression_generator.go

@@ -0,0 +1,101 @@
+package cucumberexpressions
+
+import (
+	"sort"
+	"strings"
+)
+
+type CucumberExpressionGenerator struct {
+	parameterTypeRegistry *ParameterTypeRegistry
+}
+
+func NewCucumberExpressionGenerator(parameterTypeRegistry *ParameterTypeRegistry) *CucumberExpressionGenerator {
+	return &CucumberExpressionGenerator{
+		parameterTypeRegistry: parameterTypeRegistry,
+	}
+}
+
+func (c *CucumberExpressionGenerator) GenerateExpressions(text string) []*GeneratedExpression {
+	parameterTypeCombinations := [][]*ParameterType{}
+	parameterTypeMatchers := c.createParameterTypeMatchers(text)
+	expressionTemplate := ""
+	pos := 0
+
+	for {
+		matchingParameterTypeMatchers := []*ParameterTypeMatcher{}
+		for _, parameterTypeMatcher := range parameterTypeMatchers {
+			advancedParameterTypeMatcher := parameterTypeMatcher.AdvanceTo(pos)
+			if advancedParameterTypeMatcher.Find() {
+				matchingParameterTypeMatchers = append(matchingParameterTypeMatchers, advancedParameterTypeMatcher)
+			}
+		}
+		if len(matchingParameterTypeMatchers) > 0 {
+			sort.Slice(matchingParameterTypeMatchers, func(i int, j int) bool {
+				return CompareParameterTypeMatchers(matchingParameterTypeMatchers[i], matchingParameterTypeMatchers[j]) <= 0
+			})
+
+			// Find all the best parameter type matchers, they are all candidates.
+			bestParameterTypeMatcher := matchingParameterTypeMatchers[0]
+			bestParameterTypeMatchers := []*ParameterTypeMatcher{}
+			for _, parameterTypeMatcher := range matchingParameterTypeMatchers {
+				if CompareParameterTypeMatchers(parameterTypeMatcher, bestParameterTypeMatcher) == 0 {
+					bestParameterTypeMatchers = append(bestParameterTypeMatchers, parameterTypeMatcher)
+				}
+			}
+
+			// Build a list of parameter types without duplicates. The reason there
+			// might be duplicates is that some parameter types have more than one regexp,
+			// which means multiple ParameterTypeMatcher objects will have a reference to the
+			// same ParameterType.
+			// We're sorting the list so preferential parameter types are listed first.
+			// Users are most likely to want these, so they should be listed at the top.
+			parameterTypesMap := map[*ParameterType]bool{}
+			for _, parameterTypeMatcher := range bestParameterTypeMatchers {
+				parameterTypesMap[parameterTypeMatcher.parameterType] = true
+			}
+			parameterTypes := []*ParameterType{}
+			for parameterType := range parameterTypesMap {
+				parameterTypes = append(parameterTypes, parameterType)
+			}
+			sort.Slice(parameterTypes, func(i int, j int) bool {
+				return CompareParameterTypes(parameterTypes[i], parameterTypes[j]) <= 0
+			})
+
+			parameterTypeCombinations = append(parameterTypeCombinations, parameterTypes)
+			expressionTemplate += escape(text[pos:bestParameterTypeMatcher.Start()]) + "{%s}"
+			pos = bestParameterTypeMatcher.Start() + len(bestParameterTypeMatcher.Group())
+		} else {
+			break
+		}
+
+		if pos > len(text) {
+			break
+		}
+	}
+	expressionTemplate += escape(text[pos:])
+	return NewCombinatorialGeneratedExpressionFactory(expressionTemplate, parameterTypeCombinations).GenerateExpressions()
+}
+
+func (c *CucumberExpressionGenerator) createParameterTypeMatchers(text string) []*ParameterTypeMatcher {
+	result := []*ParameterTypeMatcher{}
+	for _, parameterType := range c.parameterTypeRegistry.ParamaterTypes() {
+		if parameterType.UseForSnippets() {
+			result = append(result, c.createParameterTypeMatchers2(parameterType, text)...)
+		}
+	}
+	return result
+}
+
+func (c *CucumberExpressionGenerator) createParameterTypeMatchers2(parameterType *ParameterType, text string) []*ParameterTypeMatcher {
+	result := make([]*ParameterTypeMatcher, len(parameterType.Regexps()))
+	for i, r := range parameterType.Regexps() {
+		result[i] = NewParameterTypeMatcher(parameterType, r, text, 0)
+	}
+	return result
+}
+
+func escape(s string) string {
+	result := strings.Replace(s, "%", "%%", -1)
+	result = strings.Replace(result, `(`, `\(`, -1)
+	return strings.Replace(result, `{`, `\{`, -1)
+}