From 1956c6f906c25a07273f5de9d45cbf116a9b602e Mon Sep 17 00:00:00 2001
From: Henrixounez <30901439+Henrixounez@users.noreply.github.com>
Date: Wed, 16 Oct 2019 01:50:48 +0200
Subject: [PATCH] repl: readline line editing

---
 vlib/compiler/repl.v         | 24 ++++++++-----
 vlib/readline/readline_js.v  | 66 ++++++++++++++++++++++++++++++++++++
 vlib/readline/readline_lin.v |  8 +++--
 vlib/readline/readline_mac.v |  5 ++-
 vlib/readline/readline_win.v |  2 +-
 5 files changed, 92 insertions(+), 13 deletions(-)
 create mode 100644 vlib/readline/readline_js.v

diff --git a/vlib/compiler/repl.v b/vlib/compiler/repl.v
index 65b613634d..b7c0fb57c1 100644
--- a/vlib/compiler/repl.v
+++ b/vlib/compiler/repl.v
@@ -4,8 +4,11 @@
 
 module compiler
 
-import os
-import term
+import (
+	os
+	term
+	readline
+)
 
 struct Repl {
 mut:
@@ -81,22 +84,27 @@ pub fn run_repl() []string {
 		os.rm(temp_file.left(temp_file.len - 2))
 	}
 	mut r := Repl{}
+	mut readline := readline.Readline{}
 	vexe := os.args[0]
+	mut prompt := '>>> '
 	for {
 		if r.indent == 0 {
-			print('>>> ')
+			prompt = '>>> '
 		}
 		else {
-			print('... ')
+			prompt = '... '
 		}
-		r.line = os.get_raw_line()
-		if r.line.trim_space() == '' && r.line.ends_with('\n') {
+		mut line := readline.read_line(prompt) or {
+				break
+		}
+		if line.trim_space() == '' && line.ends_with('\n') {
 			continue
 		}
-		r.line = r.line.trim_space()
-		if r.line.len == -1 || r.line == '' || r.line == 'exit' {
+		line = line.trim_space()
+		if line.len <= -1 || line == '' || line == 'exit' {
 			break
 		}
+		r.line = line
 		if r.line == '\n' {
 			continue
 		}
diff --git a/vlib/readline/readline_js.v b/vlib/readline/readline_js.v
new file mode 100644
index 0000000000..e96014db44
--- /dev/null
+++ b/vlib/readline/readline_js.v
@@ -0,0 +1,66 @@
+// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+
+// JS version
+// Need to be implemented
+// Will serve as more advanced input method
+// Based on the work of https://github.com/AmokHuginnsson/replxx
+
+module readline
+
+import os
+
+// Only use standard os.get_line
+// Need implementation for readline capabilities
+pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
+  r.current = ''.ustring()
+  r.cursor = 0
+  r.prompt = prompt
+  r.search_index = 0
+  if r.previous_lines.len <= 1 {
+    r.previous_lines << ''.ustring()
+    r.previous_lines << ''.ustring()
+  }
+  else {
+    r.previous_lines[0] = ''.ustring()
+  }
+
+  print(r.prompt)
+  r.current = os.get_raw_line().ustring()
+
+  r.previous_lines[0] = ''.ustring()
+  r.search_index = 0
+  if r.current.s == '' {
+    return error('empty line')
+  }
+  return r.current
+}
+
+// Returns the string from the utf8 ustring
+pub fn (r mut Readline) read_line(prompt string) ?string {
+  s := r.read_line_utf8(prompt) or {
+    return error(err)
+  }
+  return s.s
+}
+
+// Standalone function without persistent functionnalities (eg: history)
+// Returns utf8 based ustring
+pub fn read_line_utf8(prompt string) ?ustring {
+  mut r := Readline{}
+  s := r.read_line_utf8(prompt) or {
+    return error(err)
+  }
+  return s
+}
+
+// Standalone function without persistent functionnalities (eg: history)
+// Return string from utf8 ustring
+pub fn read_line(prompt string) ?string {
+  mut r := Readline{}
+  s := r.read_line(prompt) or {
+    return error(err)
+  }
+  return s
+}
diff --git a/vlib/readline/readline_lin.v b/vlib/readline/readline_lin.v
index 591211e23e..1f13b6be5f 100644
--- a/vlib/readline/readline_lin.v
+++ b/vlib/readline/readline_lin.v
@@ -149,7 +149,7 @@ pub fn read_line(prompt string) ?string {
   return s
 }
 
-fn (r Readline) analyse(c byte) Action {
+fn (r Readline) analyse(c int) Action {
   switch c {
     case `\0`: return Action.eof
     case 0x3 : return Action.eof // End of Text
@@ -295,7 +295,9 @@ fn (r mut Readline) refresh_line() {
 fn (r mut Readline) eof() bool {
   r.previous_lines.insert(1, r.current)
   r.cursor = r.current.len
-  r.refresh_line()
+  if r.is_tty {
+    r.refresh_line()
+  }
   return true
 }
 
@@ -337,8 +339,8 @@ fn (r mut Readline) commit_line() bool {
   a := '\n'.ustring()
   r.current = r.current + a
   r.cursor = r.current.len
-  r.refresh_line()
   if r.is_tty {
+    r.refresh_line()
     println('')
   }
   return true
diff --git a/vlib/readline/readline_mac.v b/vlib/readline/readline_mac.v
index f177876132..7fd1a116cb 100644
--- a/vlib/readline/readline_mac.v
+++ b/vlib/readline/readline_mac.v
@@ -27,8 +27,11 @@ pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
   }
 
   print(r.prompt)
-  r.current = os.get_line().ustring()
+  line := os.get_raw_line()
 
+  if line.len >= 0 {
+    r.current = line.ustring()
+  }
   r.previous_lines[0] = ''.ustring()
   r.search_index = 0
   if r.current.s == '' {
diff --git a/vlib/readline/readline_win.v b/vlib/readline/readline_win.v
index 9eda679d52..5b7c17457f 100644
--- a/vlib/readline/readline_win.v
+++ b/vlib/readline/readline_win.v
@@ -27,7 +27,7 @@ pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
   }
 
   print(r.prompt)
-  r.current = os.get_line().ustring()
+  r.current = os.get_raw_line().ustring()
 
   r.previous_lines[0] = ''.ustring()
   r.search_index = 0