From abf15e863cf8adb8f141f1f9673c373a935c97d0 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Thu, 2 Apr 2020 19:21:12 +0300
Subject: [PATCH] v2: compile vrepl, 'fn main(){println(2+2)}' runs now

It works if you give it complete V programs like
fn main(){println(2+2)}
but not for single expressions like 2+2 or statements like a:='abc'
---
 vlib/builtin/string.v          |  6 +++++-
 vlib/readline/readline_linux.v | 18 ++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/vlib/builtin/string.v b/vlib/builtin/string.v
index 196a279bc5..fb77d9cf30 100644
--- a/vlib/builtin/string.v
+++ b/vlib/builtin/string.v
@@ -916,6 +916,10 @@ pub fn (s mut []string) sort_by_len() {
 	s.sort_with_compare(compare_strings_by_len)
 }
 
+pub fn (s ustring) str() string {
+   return s.s
+}
+
 pub fn (s string) ustring() ustring {
 	mut res := ustring{
 		s: s
@@ -985,7 +989,7 @@ fn (u ustring) ge(a ustring) bool {
 	return !u.lt(a)
 }
 
-fn (u ustring) add(a ustring) ustring {
+pub fn (u ustring) add(a ustring) ustring {
 	mut res := ustring{
 		s: u.s + a.s
 		runes: new_array(0, u.s.len + a.s.len, sizeof(int))
diff --git a/vlib/readline/readline_linux.v b/vlib/readline/readline_linux.v
index 9314c25034..327cb794f5 100644
--- a/vlib/readline/readline_linux.v
+++ b/vlib/readline/readline_linux.v
@@ -313,7 +313,8 @@ fn shift_cursor(xpos int, yoffset int) {
   print('\x1b[${xpos + 1}G')
 }
 
-fn calculate_screen_position(x_in int, y_in int, screen_columns int, char_count int, out mut []int) {
+fn calculate_screen_position(x_in int, y_in int, screen_columns int, char_count int, inp []int) []int {
+  mut out := inp
   mut x := x_in
   mut y := y_in
   out[0] = x
@@ -330,15 +331,16 @@ fn calculate_screen_position(x_in int, y_in int, screen_columns int, char_count
     out[0] = 0
     out[1]++
   }
+  return out
 }
 
 // Will redraw the line
 fn (r mut Readline) refresh_line() {
   mut end_of_input := [0, 0]
-  calculate_screen_position(r.prompt.len, 0, get_screen_columns(), r.current.len, mut end_of_input)
+  end_of_input = calculate_screen_position(r.prompt.len, 0, get_screen_columns(), r.current.len, end_of_input)
   end_of_input[1] += r.current.count('\n'.ustring())
   mut cursor_pos := [0, 0]
-  calculate_screen_position(r.prompt.len, 0, get_screen_columns(), r.cursor, mut cursor_pos)
+  cursor_pos = calculate_screen_position(r.prompt.len, 0, get_screen_columns(), r.cursor, cursor_pos)
 
   shift_cursor(0, -r.cursor_row_offset)
   term.erase_toend()
@@ -363,9 +365,9 @@ fn (r mut Readline) eof() bool {
 
 fn (r mut Readline) insert_character(c int) {
   if !r.overwrite || r.cursor == r.current.len {
-    r.current = r.current.left(r.cursor).ustring() + utf32_to_str(u32(c)).ustring() + r.current.right(r.cursor).ustring()
+    r.current = r.current.left(r.cursor).ustring().add( utf32_to_str(u32(c)).ustring() ).add( r.current.right(r.cursor).ustring() )
   } else {
-    r.current = r.current.left(r.cursor).ustring() + utf32_to_str(u32(c)).ustring() + r.current.right(r.cursor + 1).ustring()
+    r.current = r.current.left(r.cursor).ustring().add( utf32_to_str(u32(c)).ustring() ).add( r.current.right(r.cursor + 1).ustring() )
   }
   r.cursor++
   // Refresh the line to add the new character
@@ -380,7 +382,7 @@ fn (r mut Readline) delete_character() {
     return
   }
   r.cursor--
-  r.current = r.current.left(r.cursor).ustring() + r.current.right(r.cursor + 1).ustring()
+  r.current = r.current.left(r.cursor).ustring().add( r.current.right(r.cursor + 1).ustring() )
   r.refresh_line()
 }
 
@@ -389,7 +391,7 @@ fn (r mut Readline) suppr_character() {
   if r.cursor > r.current.len {
     return
   }
-  r.current = r.current.left(r.cursor).ustring() + r.current.right(r.cursor + 1).ustring()
+  r.current = r.current.left(r.cursor).ustring().add( r.current.right(r.cursor + 1).ustring() )
   r.refresh_line()
 }
 
@@ -397,7 +399,7 @@ fn (r mut Readline) suppr_character() {
 fn (r mut Readline) commit_line() bool {
   r.previous_lines.insert(1, r.current)
   a := '\n'.ustring()
-  r.current = r.current + a
+  r.current = r.current.add( a )
   r.cursor = r.current.len
   if r.is_tty {
     r.refresh_line()