1 files changed, 307 insertions, 0 deletions
diff --git a/cli/parser.go b/cli/parser.go
new file mode 100644
index 0000000..433a4b1
--- /dev/null
+++ b/cli/parser.go
@@ -0,0 +1,307 @@
+package cli
+
+import (
+    "fmt"
+    "strconv"
+)
+
+type Parser interface {
+    Match([]string) ([]string, bool)
+    Capture([]string) ([]string, map[string]string)
+}
+
+type CompleteParser struct {
+    parsers []Parser
+}
+
+func (self CompleteParser) Match(values []string) ([]string, bool) {
+    remainingValues := values
+
+    for _, parser := range self.parsers {
+        var ok bool
+        remainingValues, ok = parser.Match(remainingValues)
+        if !ok {
+            return remainingValues, false
+        }
+    }
+
+    return remainingValues, len(remainingValues) == 0
+}
+
+func (self CompleteParser) Capture(values []string) ([]string, map[string]string) {
+    remainingValues := values
+    data := map[string]string{}
+
+    for _, parser := range self.parsers {
+        var captured map[string]string
+        remainingValues, captured = parser.Capture(remainingValues)
+        for key, value := range captured {
+            data[key] = value
+        }
+    }
+
+    return remainingValues, data
+}
+
+func (self CompleteParser) String() string {
+    return fmt.Sprintf("CompleteParser %v", self.parsers)
+}
+
+
+type EqualParser struct {
+    value string
+}
+
+func (self EqualParser) Match(values []string) ([]string, bool) {
+    if len(values) == 0 {
+        return values, false
+    }
+
+    if self.value == values[0] {
+        return values[1:], true
+    }
+
+    return values, false
+}
+
+func (self EqualParser) Capture(values []string) ([]string, map[string]string) {
+    remainingValues, _ := self.Match(values)
+    return remainingValues, nil
+}
+
+func (self EqualParser) String() string {
+    return fmt.Sprintf("EqualParser '%s'", self.value)
+}
+
+
+type CaptureGroupParser struct {
+    value string
+}
+
+func (self CaptureGroupParser) Match(values []string) ([]string, bool) {
+    if len(values) == 0 {
+        return values, false
+    }
+
+    return values[1:], true
+}
+
+func (self CaptureGroupParser) key() string {
+    return self.value[1:len(self.value) - 1]
+}
+
+func (self CaptureGroupParser) Capture(values []string) ([]string, map[string]string) {
+    if remainingValues, ok := self.Match(values); ok {
+        return remainingValues, map[string]string{self.key(): values[0]}
+    }
+
+    return values, nil
+}
+
+func (self CaptureGroupParser) String() string {
+    return fmt.Sprintf("CaptureGroupParser '%s'", self.value)
+}
+
+
+
+type BoolFlagParser struct {
+    pattern string
+    key string
+    omitValue bool
+    defaultValue bool
+}
+
+func (self BoolFlagParser) Match(values []string) ([]string, bool) {
+    if self.omitValue {
+        if len(values) == 0 {
+            return values, false
+        }
+
+        if self.pattern == values[0] {
+            return values[1:], true
+        }
+
+        return values, false
+    } else {
+        if len(values) < 2 {
+            return values, false
+        }
+
+        if self.pattern != values[0] {
+            return values, false
+        }
+
+        // Check that value is a valid boolean
+        if _, err := strconv.ParseBool(values[1]); err != nil {
+            return values, false
+        }
+
+        return values[2:], true
+    }
+}
+
+func (self BoolFlagParser) Capture(values []string) ([]string, map[string]string) {
+    remainingValues, ok := self.Match(values)
+    if !ok && !self.omitValue {
+        return remainingValues, map[string]string{self.key: fmt.Sprintf("%t", self.defaultValue)}
+    }
+    return remainingValues, map[string]string{self.key: fmt.Sprintf("%t", ok)}
+}
+
+func (self BoolFlagParser) String() string {
+    return fmt.Sprintf("BoolFlagParser '%s'", self.pattern)
+}
+
+type StringFlagParser struct {
+    pattern string
+    key string
+    defaultValue string
+}
+
+func (self StringFlagParser) Match(values []string) ([]string, bool) {
+    if len(values) < 2 {
+        return values, false
+    }
+
+    if self.pattern != values[0] {
+        return values, false
+    }
+
+    return values[2:], true
+}
+
+func (self StringFlagParser) Capture(values []string) ([]string, map[string]string) {
+    remainingValues, ok := self.Match(values)
+    if ok {
+        return remainingValues, map[string]string{self.key: values[1]}
+    }
+
+    return values, map[string]string{self.key: self.defaultValue}
+}
+
+func (self StringFlagParser) String() string {
+    return fmt.Sprintf("StringFlagParser '%s'", self.pattern)
+}
+
+type IntFlagParser struct {
+    pattern string
+    key string
+    defaultValue int64
+}
+
+func (self IntFlagParser) Match(values []string) ([]string, bool) {
+    if len(values) < 2 {
+        return values, false
+    }
+
+    if self.pattern != values[0] {
+        return values, false
+    }
+
+    // Check that value is a valid integer
+    if _, err := strconv.ParseInt(values[1], 10, 64); err != nil {
+        return values, false
+    }
+
+    return values[2:], true
+}
+
+func (self IntFlagParser) Capture(values []string) ([]string, map[string]string) {
+    remainingValues, ok := self.Match(values)
+    if ok {
+        return remainingValues, map[string]string{self.key: values[1]}
+    }
+
+    return values, map[string]string{self.key: fmt.Sprintf("%d", self.defaultValue)}
+}
+
+func (self IntFlagParser) String() string {
+    return fmt.Sprintf("IntFlagParser '%s'", self.pattern)
+}
+
+
+type FlagParser struct {
+    parsers []Parser
+}
+
+func (self FlagParser) Match(values []string) ([]string, bool) {
+    remainingValues := values
+    var oneOrMoreMatches bool
+
+    for _, parser := range self.parsers {
+        var ok bool
+        remainingValues, ok = parser.Match(remainingValues)
+        if ok {
+            oneOrMoreMatches = true
+        }
+    }
+
+    // Recurse while we have one or more matches
+    if oneOrMoreMatches {
+        return self.Match(remainingValues)
+    }
+
+    return remainingValues, true
+}
+
+func (self FlagParser) Capture(values []string) ([]string, map[string]string) {
+    data := map[string]string{}
+    remainingValues := values
+
+    for _, parser := range self.parsers {
+        var captured map[string]string
+        remainingValues, captured = parser.Capture(remainingValues)
+        for key, value := range captured {
+            // Skip value if it already exists and new value is an empty string
+            if _, exists := data[key]; exists && value == "" {
+                continue
+            }
+
+            data[key] = value
+        }
+    }
+    return remainingValues, data
+}
+
+func (self FlagParser) String() string {
+    return fmt.Sprintf("FlagParser %v", self.parsers)
+}
+
+
+type ShortCircuitParser struct {
+    parsers []Parser
+}
+
+func (self ShortCircuitParser) Match(values []string) ([]string, bool) {
+    remainingValues := values
+
+    for _, parser := range self.parsers {
+        var ok bool
+        remainingValues, ok = parser.Match(remainingValues)
+        if ok {
+            return remainingValues, true
+        }
+    }
+
+    return remainingValues, false
+}
+
+func (self ShortCircuitParser) Capture(values []string) ([]string, map[string]string) {
+    if len(self.parsers) == 0 {
+        return values, nil
+    }
+
+    for _, parser := range self.parsers {
+        if _, ok := parser.Match(values); ok {
+            return parser.Capture(values)
+        }
+    }
+
+    // No parsers matched at this point,
+    // just return the capture value of the first one
+    return self.parsers[0].Capture(values)
+}
+
+func (self ShortCircuitParser) String() string {
+    return fmt.Sprintf("ShortCircuitParser %v", self.parsers)
+}