From 62cb48d2526285843151fdec450f8f215744efb1 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Sat, 16 May 2020 22:03:28 +0300
Subject: [PATCH] repl: treat middle imports in a more forgiving way

---
 cmd/tools/vrepl.v      | 54 ++++++++++++++++++++++++++----------------
 vlib/v/parser/module.v |  5 ++++
 2 files changed, 38 insertions(+), 21 deletions(-)

diff --git a/cmd/tools/vrepl.v b/cmd/tools/vrepl.v
index 414cf75c7b..a18d380e5d 100644
--- a/cmd/tools/vrepl.v
+++ b/cmd/tools/vrepl.v
@@ -12,13 +12,15 @@ import v.util
 
 struct Repl {
 mut:
-	indent         int
-	in_func        bool
-	line           string
-	lines          []string
-	temp_lines     []string
-	functions_name []string
-	functions      []string
+	indent         int      // indentation level
+	in_func        bool     // are we inside a new custom user function
+	line           string   // the current line entered by the user
+	//
+	imports        []string // all the import statements
+	functions      []string // all the user function declarations
+	functions_name []string // all the user function names
+	lines          []string // all the other lines/statements
+	temp_lines     []string // all the temporary expressions/printlns
 }
 
 fn (r mut Repl) checks() bool {
@@ -58,6 +60,17 @@ fn (r &Repl) function_call(line string) bool {
 	return false
 }
 
+fn (r &Repl) current_source_code(should_add_temp_lines bool) string {
+	mut all_lines := []string{}
+	all_lines << r.imports
+	all_lines << r.functions
+	all_lines << r.lines
+	if should_add_temp_lines {
+		all_lines << r.temp_lines
+	}
+	return all_lines.join('\n')
+}
+
 fn repl_help() {
 	println(util.full_v_version())
 	println('
@@ -143,16 +156,16 @@ fn run_repl(workdir string, vrepl_prefix string) {
 			}
 			r.line = ''
 		}
+		if r.line == 'debug_repl' {
+			eprintln('repl: $r')
+			continue
+		}
 		if r.line == 'reset' {
 		    r = Repl{}
 			continue
 		}
 		if r.line == 'list' {
-			mut all_lines := []string{}
-			all_lines << r.functions
-			all_lines << r.lines
-			all_lines << r.temp_lines
-			source_code := all_lines.join('\n')
+			source_code := r.current_source_code(true)
 			println('//////////////////////////////////////////////////////////////////////////////////////')
 			println(source_code)
 			println('//////////////////////////////////////////////////////////////////////////////////////')
@@ -162,7 +175,7 @@ fn run_repl(workdir string, vrepl_prefix string) {
 		// but don't add this print call to the `lines` array,
 		// so that it doesn't get called during the next print.
 		if r.line.starts_with('print') {
-			source_code := r.functions.join('\n') + r.lines.join('\n') + '\n' + r.line + '\n'
+			source_code := r.current_source_code(false) + '\n${r.line}\n'
 			os.write_file(file, source_code)
 			s := os.exec('"$vexe" -repl run $file') or {
 				rerror(err)
@@ -195,10 +208,10 @@ fn run_repl(workdir string, vrepl_prefix string) {
 				temp_flag = true
 			}
 			mut temp_source_code := ''
-			if temp_line.starts_with('import') {
-				temp_source_code = r.functions.join('\n') + temp_line + '\n'
+			if temp_line.starts_with('import ') {
+				temp_source_code = '${temp_line}\n' + r.current_source_code(false)
 			} else {
-				temp_source_code = r.functions.join('\n') + r.lines.join('\n') + '\n' + r.temp_lines.join('\n') + '\n' + temp_line + '\n'
+				temp_source_code = r.current_source_code(true) + '\n${temp_line}\n'
 			}
 			os.write_file(temp_file, temp_source_code)
 			s := os.exec('"$vexe" -repl run $temp_file') or {
@@ -212,11 +225,10 @@ fn run_repl(workdir string, vrepl_prefix string) {
 					}
 					r.temp_lines.delete(0)
 				}
-				if r.line.starts_with('import') {
-					mut lines := []string{cap: r.lines.len+1}
-					lines << r.line
-					lines << r.lines
-					r.lines = lines
+				if r.line.starts_with('import ') {
+					mut imports := r.imports
+					r.imports = [r.line]
+					r.imports << imports
 				} else {
 					r.lines << r.line
 				}
diff --git a/vlib/v/parser/module.v b/vlib/v/parser/module.v
index 10c52bce66..ae31c5bc47 100644
--- a/vlib/v/parser/module.v
+++ b/vlib/v/parser/module.v
@@ -39,5 +39,10 @@ fn (p mut Parser) check_unused_imports() {
 	if output == '' {
 		return
 	}
+	if p.pref.is_repl {
+		// The REPL should be much more liberal, and should not warn about
+		// unused imports, because they probably will be in the next few lines...
+		return
+	}
 	eprintln('`$p.file_name` warning: the following imports were never used: $output')
 }