refactor: use language context to display segment

relates to #239

docs/docs/segment-python.md

@@ -32,3 +32,4 @@ Supports conda, virtualenv and pyenv.
 - display_mode: `string` - determines when the segment is displayed
   - `always`: The segment is always displayed
   - `files`: The segment is only displayed when `*.py` or `*.ipynb` files are present (default)
+  - `environment`: The segment is only displayed when a virtual env is present

src/segment_language.go

@@ -2,6 +2,10 @@ package main
 
 import "errors"
 
+type loadContext func()
+
+type inContext func() bool
+
 type language struct {
 	props        *properties
 	env          environmentInfo
@@ -12,6 +16,8 @@ type language struct {
 	versionRegex string
 	version      string
 	exitCode     int
+	loadContext  loadContext
+	inContext    inContext
 }
 
 const (
@@ -21,6 +27,8 @@ const (
 	DisplayModeAlways string = "always"
 	// DisplayModeFiles displays the segment when the current folder contains certain extensions
 	DisplayModeFiles string = "files"
+	// DisplayModeEnvironment displays the segment when the environment has a language's context
+	DisplayModeEnvironment string = "environment"
 	// MissingCommandTextProperty sets the text to display when the command is not present in the system
 	MissingCommandTextProperty Property = "missing_command_text"
 	// MissingCommandText displays empty string by default
@@ -43,10 +51,12 @@ func (l *language) string() string {
 func (l *language) enabled() bool {
 	displayMode := l.props.getString(DisplayMode, DisplayModeFiles)
 	displayVersion := l.props.getBool(DisplayVersion, true)
-
+	l.loadLanguageContext()
 	switch displayMode {
 	case DisplayModeAlways:
 		return (!displayVersion || l.hasCommand())
+	case DisplayModeEnvironment:
+		return l.inLanguageContext()
 	case DisplayModeFiles:
 		fallthrough
 	default:
@@ -98,3 +108,17 @@ func (l *language) hasCommand() bool {
 	}
 	return true
 }
+
+func (l *language) loadLanguageContext() {
+	if l.loadContext == nil {
+		return
+	}
+	l.loadContext()
+}
+
+func (l *language) inLanguageContext() bool {
+	if l.inContext == nil {
+		return false
+	}
+	return l.inContext()
+}

src/segment_python.go

@@ -31,17 +31,19 @@ func (p *python) init(props *properties, env environmentInfo) {
 		versionParam: "--version",
 		extensions:   []string{"*.py", "*.ipynb"},
 		versionRegex: `Python (?P<version>[0-9]+.[0-9]+.[0-9]+)`,
+		loadContext:  p.loadContext,
+		inContext:    p.inContext,
 	}
 }
 
 func (p *python) enabled() bool {
-	if !p.language.enabled() {
+	return p.language.enabled()
-		return false
+}
-	}
+
+func (p *python) loadContext() {
 	venvVars := []string{
 		"VIRTUAL_ENV",
 		"CONDA_ENV_PATH",
-		"CONDA_DEFAULT_ENV",
 		"PYENV_VERSION",
 	}
 	var venv string
@@ -52,5 +54,8 @@ func (p *python) enabled() bool {
 			break
 		}
 	}
-	return true
+}
+
+func (p *python) inContext() bool {
+	return p.venvName != ""
 }

src/segment_python_test.go

@@ -9,7 +9,6 @@ import (
 type pythonArgs struct {
 	virtualEnvName string
 	condaEnvName   string
-	condaDefaultName string
 	pyEnvName      string
 	displayVersion bool
 }
@@ -21,7 +20,6 @@ func bootStrapPythonTest(args *pythonArgs) *python {
 	env.On("hasFiles", "*.py").Return(true)
 	env.On("getenv", "VIRTUAL_ENV").Return(args.virtualEnvName)
 	env.On("getenv", "CONDA_ENV_PATH").Return(args.condaEnvName)
-	env.On("getenv", "CONDA_DEFAULT_ENV").Return(args.condaDefaultName)
 	env.On("getenv", "PYENV_VERSION").Return(args.pyEnvName)
 	env.On("getPathSeperator", nil).Return("")
 	props := &properties{
@@ -55,16 +53,6 @@ func TestPythonCondaEnv(t *testing.T) {
 	assert.Equal(t, expected, python.string())
 }
 
-func TestPythonCondaDefaultName(t *testing.T) {
-	expected := "CONDADEF"
-	args := &pythonArgs{
-		condaDefaultName: expected,
-	}
-	python := bootStrapPythonTest(args)
-	assert.True(t, python.enabled())
-	assert.Equal(t, expected, python.string())
-}
-
 func TestPythonPyEnv(t *testing.T) {
 	expected := "PYENV"
 	args := &pythonArgs{
@@ -86,3 +74,19 @@ func TestPythonPyEnvWithVersion(t *testing.T) {
 	assert.Equal(t, expected, python.string())
 	assert.Equal(t, "3.8.4", python.language.version)
 }
+
+func TestPythonPythonInContext(t *testing.T) {
+	args := &pythonArgs{
+		pyEnvName:      "PYENV",
+		displayVersion: true,
+	}
+	python := bootStrapPythonTest(args)
+	python.loadContext()
+	assert.True(t, python.inContext())
+}
+
+func TestPythonPythonNotInContext(t *testing.T) {
+	python := bootStrapPythonTest(&pythonArgs{})
+	python.loadContext()
+	assert.False(t, python.inContext())
+}