Add vendor files for go build

vendor/github.com/alecthomas/chroma/mutators.go

@@ -0,0 +1,131 @@
+package chroma
+
+import (
+	"fmt"
+	"strings"
+)
+
+// A Mutator modifies the behaviour of the lexer.
+type Mutator interface {
+	// Mutate the lexer state machine as it is processing.
+	Mutate(state *LexerState) error
+}
+
+// A LexerMutator is an additional interface that a Mutator can implement
+// to modify the lexer when it is compiled.
+type LexerMutator interface {
+	// Rules are the lexer rules, state is the state key for the rule the mutator is associated with.
+	MutateLexer(rules CompiledRules, state string, rule int) error
+}
+
+// A MutatorFunc is a Mutator that mutates the lexer state machine as it is processing.
+type MutatorFunc func(state *LexerState) error
+
+func (m MutatorFunc) Mutate(state *LexerState) error { return m(state) } // nolint
+
+// Mutators applies a set of Mutators in order.
+func Mutators(modifiers ...Mutator) MutatorFunc {
+	return func(state *LexerState) error {
+		for _, modifier := range modifiers {
+			if err := modifier.Mutate(state); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+}
+
+type includeMutator struct {
+	state string
+}
+
+// Include the given state.
+func Include(state string) Rule {
+	return Rule{Mutator: &includeMutator{state}}
+}
+
+func (i *includeMutator) Mutate(s *LexerState) error {
+	return fmt.Errorf("should never reach here Include(%q)", i.state)
+}
+
+func (i *includeMutator) MutateLexer(rules CompiledRules, state string, rule int) error {
+	includedRules, ok := rules[i.state]
+	if !ok {
+		return fmt.Errorf("invalid include state %q", i.state)
+	}
+	rules[state] = append(rules[state][:rule], append(includedRules, rules[state][rule+1:]...)...)
+	return nil
+}
+
+type combinedMutator struct {
+	states []string
+}
+
+// Combined creates a new anonymous state from the given states, and pushes that state.
+func Combined(states ...string) Mutator {
+	return &combinedMutator{states}
+}
+
+func (c *combinedMutator) Mutate(s *LexerState) error {
+	return fmt.Errorf("should never reach here Combined(%v)", c.states)
+}
+
+func (c *combinedMutator) MutateLexer(rules CompiledRules, state string, rule int) error {
+	name := "__combined_" + strings.Join(c.states, "__")
+	if _, ok := rules[name]; !ok {
+		combined := []*CompiledRule{}
+		for _, state := range c.states {
+			rules, ok := rules[state]
+			if !ok {
+				return fmt.Errorf("invalid combine state %q", state)
+			}
+			combined = append(combined, rules...)
+		}
+		rules[name] = combined
+	}
+	rules[state][rule].Mutator = Push(name)
+	return nil
+}
+
+// Push states onto the stack.
+func Push(states ...string) MutatorFunc {
+	return func(s *LexerState) error {
+		if len(states) == 0 {
+			s.Stack = append(s.Stack, s.State)
+		} else {
+			for _, state := range states {
+				if state == "#pop" {
+					s.Stack = s.Stack[:len(s.Stack)-1]
+				} else {
+					s.Stack = append(s.Stack, state)
+				}
+			}
+		}
+		return nil
+	}
+}
+
+// Pop state from the stack when rule matches.
+func Pop(n int) MutatorFunc {
+	return func(state *LexerState) error {
+		if len(state.Stack) == 0 {
+			return fmt.Errorf("nothing to pop")
+		}
+		state.Stack = state.Stack[:len(state.Stack)-n]
+		return nil
+	}
+}
+
+// Default returns a Rule that applies a set of Mutators.
+func Default(mutators ...Mutator) Rule {
+	return Rule{Mutator: Mutators(mutators...)}
+}
+
+// Stringify returns the raw string for a set of tokens.
+func Stringify(tokens ...Token) string {
+	out := []string{}
+	for _, t := range tokens {
+		out = append(out, t.Value)
+	}
+	return strings.Join(out, "")
+}