Document changes in the README

README.md

@@ -10,6 +10,16 @@ It's a great library but it's been abandoned
 for quite a while.
 This project aims to continue its development.
 
+The library has been rewritten in many aspects, fixing existing bugs and adding new essential functionality.
+
+Most notable changes include:
+- Support for custom syntax highlighting with a lexer
+- Multiline editing
+- A scrolling buffer is used for displaying the current content which makes it possible to edit text of arbitrary length (only the visible part of the text is rendered)
+- Support for automatic indentation when pressing <kbd>Enter</kbd> and the input is incomplete or for executing the input when it is complete. This is determined by a custom callback function.
+
+I highly encourage you to see the [changelog](CHANGELOG.md) which fully documents the changes that have been made.
+
 ---
 
 A library for building powerful interactive prompts inspired by [python-prompt-toolkit](https://github.com/jonathanslenders/python-prompt-toolkit),
@@ -49,9 +59,21 @@ func main() {
 
 ## Features
 
+### Automatic indentation with a custom callback
+
+![automatic indentation](readme/automatic-indentation.gif)
+
+### Multiline editing with scrolling
+
+![multiline editing](readme/multiline-editing.gif)
+
+### Custom syntax highlighting
+
+![syntax highlighting](readme/syntax-highlighting.gif)
+
 ### Powerful auto-completion
 
-[![demo](https://github.com/c-bata/assets/raw/master/go-prompt/kube-prompt.gif)](https://github.com/c-bata/kube-prompt)
+[![autocompletion](https://github.com/c-bata/assets/raw/master/go-prompt/kube-prompt.gif)](https://github.com/c-bata/kube-prompt)
 
 (This is a GIF animation of kube-prompt.)
 

_example/README.md

@@ -9,6 +9,12 @@ Uses a custom lexer that colours every character with an even index green.
 
 Shows you how to hook up a custom lexer for syntax highlighting.
 
+## automatic indenter
+
+Inserts a newline and indentation when the <kbd>Enter</kbd> key is pressed unless the input ends with a curly brace `}` and the amount of opening and ending braces is the same (then it gets printed).
+
+Shows you how to define a custom callback which determines whether the input is complete and should be executed or a newline with indentation should be inserted (after <kbd>Enter</kbd> has been pressed).
+
 ## bang-executor
 
 Inserts a newline when the <kbd>Enter</kbd> key is pressed unless the input ends with an exclamation point `!` (then it gets printed).

_example/automatic-indenter/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/elk-language/go-prompt"
+)
+
+func main() {
+	p := prompt.New(
+		executor,
+		prompt.WithPrefix(">>> "),
+		prompt.WithExecuteOnEnterCallback(ExecuteOnEnter),
+	)
+
+	p.Run()
+}
+
+func ExecuteOnEnter(input string, indentSize int) (int, bool) {
+	lines := strings.SplitAfter(input, "\n")
+	var spaces int
+	if len(lines) > 0 {
+		lastLine := lines[len(lines)-1]
+		for _, char := range lastLine {
+			if char == '}' {
+				spaces -= 2 * indentSize
+				break
+			}
+			if char != ' ' {
+				break
+			}
+			spaces++
+		}
+	}
+
+	char, _ := utf8.DecodeLastRuneInString(input)
+	return 1 + spaces/indentSize, char == '}' && strings.Count(input, "}") == strings.Count(input, "{")
+}
+
+func executor(s string) {
+	fmt.Println("Your input: " + s)
+}

_example/bang-executor/main.go

@@ -23,5 +23,5 @@ func ExecuteOnEnter(input string, indentSize int) (int, bool) {
 }
 
 func executor(s string) {
-	fmt.Println("You printed: " + s)
+	fmt.Println("Your input: " + s)
 }

_example/build.sh

@@ -12,3 +12,4 @@ go build -o ${BIN_DIR}/simple-echo ${DIR}/simple-echo/main.go
 go build -o ${BIN_DIR}/simple-echo-cjk-cyrillic ${DIR}/simple-echo/cjk-cyrillic/main.go
 go build -o ${BIN_DIR}/even-lexer ${DIR}/even-lexer/main.go
 go build -o ${BIN_DIR}/bang-executor ${DIR}/bang-executor/main.go
+go build -o ${BIN_DIR}/automatic-indenter ${DIR}/automatic-indenter/main.go

_example/even-lexer/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"unicode"
 	"unicode/utf8"
 
 	"github.com/elk-language/go-prompt"
@@ -11,13 +12,15 @@ import (
 func main() {
 	p := prompt.New(
 		executor,
-		prompt.WithLexer(prompt.NewEagerLexer(lexer)),
+		prompt.WithLexer(prompt.NewEagerLexer(wordLexer)),
+		prompt.WithLexer(prompt.NewEagerLexer(charLexer)), // the last one overrides the other
 	)
 
 	p.Run()
 }
 
-func lexer(line string) []prompt.Token {
+// colors every other character green
+func charLexer(line string) []prompt.Token {
 	var elements []prompt.Token
 
 	for i, value := range line {
@@ -37,6 +40,47 @@ func lexer(line string) []prompt.Token {
 	return elements
 }
 
+// colors every other word green
+func wordLexer(line string) []prompt.Token {
+	if len(line) == 0 {
+		return nil
+	}
+
+	var elements []prompt.Token
+	var currentByte strings.ByteNumber
+	var wordIndex int
+	var lastChar rune
+
+	var color prompt.Color
+	for i, char := range line {
+		currentByte = strings.ByteNumber(i)
+		if unicode.IsSpace(char) {
+			if wordIndex%2 == 0 {
+				color = prompt.Green
+			} else {
+				color = prompt.White
+			}
+
+			element := prompt.NewSimpleToken(color, currentByte)
+			elements = append(elements, element)
+			wordIndex++
+			continue
+		}
+		lastChar = char
+	}
+	if !unicode.IsSpace(lastChar) {
+		if wordIndex%2 == 0 {
+			color = prompt.Green
+		} else {
+			color = prompt.White
+		}
+		element := prompt.NewSimpleToken(color, currentByte)
+		elements = append(elements, element)
+	}
+
+	return elements
+}
+
 func executor(s string) {
-	fmt.Println("You printed: " + s)
+	fmt.Println("Your input: " + s)
 }