fmt: improve string quotes (#8075)

vlib/builtin/array.v

@@ -474,9 +474,9 @@ pub fn (a []string) str() string {
 	sb.write('[')
 	for i in 0 .. a.len {
 		val := a[i]
-		sb.write("\'")
+		sb.write("'")
 		sb.write(val)
-		sb.write("\'")
+		sb.write("'")
 		if i < a.len - 1 {
 			sb.write(', ')
 		}

vlib/flag/flag_test.v

@@ -137,7 +137,7 @@ fn test_finalize_returns_error_for_unknown_flags() {
 	mut fp := flag.new_flag_parser(['--known', '--unknown'])
 	fp.bool('known', 0, false, '')
 	finalized := fp.finalize() or {
-		assert err == "Unknown argument \'unknown\'"
+		assert err == "Unknown argument 'unknown'"
 		return
 	}
 	assert finalized.len < 0 // expect error to be returned

vlib/os/os.v

@@ -35,7 +35,7 @@ pub fn cp_all(src string, dst string, overwrite bool) ? {
 	source_path := real_path(src)
 	dest_path := real_path(dst)
 	if !exists(source_path) {
-		return error("Source path doesn\'t exist")
+		return error("Source path doesn't exist")
 	}
 	// single file copy
 	if !is_dir(source_path) {

vlib/v/builder/cc.v

@@ -510,7 +510,7 @@ fn (mut v Builder) cc() {
 		if v.pref.os == .ios {
 			ios_sdk := if v.pref.is_ios_simulator { 'iphonesimulator' } else { 'iphoneos' }
 			ios_sdk_path_res := os.exec('xcrun --sdk $ios_sdk --show-sdk-path') or {
-				panic("Couldn\'t find iphonesimulator")
+				panic("Couldn't find iphonesimulator")
 			}
 			mut isysroot := ios_sdk_path_res.output.replace('\n', '')
 			ccompiler = 'xcrun --sdk iphoneos clang -isysroot $isysroot'

vlib/v/fmt/fmt.v

@@ -10,6 +10,7 @@ import strings
 import v.util
 
 const (
+	bs      = '\\'
 	tabs    = ['', '\t', '\t\t', '\t\t\t', '\t\t\t\t', '\t\t\t\t\t', '\t\t\t\t\t\t', '\t\t\t\t\t\t\t',
 		'\t\t\t\t\t\t\t\t',
 	]
@@ -1185,15 +1186,28 @@ pub fn (mut f Fmt) expr(node ast.Expr) {
 			f.write('}')
 		}
 		ast.StringLiteral {
+			use_double_quote := node.val.contains("'") && !node.val.contains('"')
 			if node.is_raw {
 				f.write('r')
 			} else if node.language == table.Language.c {
 				f.write('c')
 			}
-			if node.val.contains("'") && !node.val.contains('"') {
-				f.write('"$node.val"')
+			if node.is_raw {
+				if use_double_quote {
+					f.write('"$node.val"')
+				} else {
+					f.write("'$node.val'")
+				}
 			} else {
-				f.write("'$node.val'")
+				unescaped_val := node.val.replace('$bs$bs', '\x01').replace_each(["$bs'", "'",
+					'$bs"', '"'])
+				if use_double_quote {
+					s := unescaped_val.replace_each(['\x01', '$bs$bs', '"', '$bs"'])
+					f.write('"$s"')
+				} else {
+					s := unescaped_val.replace_each(['\x01', '$bs$bs', "'", "$bs'"])
+					f.write("'$s'")
+				}
 			}
 		}
 		ast.StringInterLiteral {

vlib/v/fmt/tests/string_quotes_expected.vv

@@ -3,9 +3,8 @@ fn main() {
 	println('This is correct !')
 	println("It's okay")
 	println('This is "too"')
-	// TODO
-	// 'I\'m not correctly formatted' => "I'm not correctly formatted"
-	// "\"Everything on the internet is true\" - Albert Einstein, 1965" => '"Everything on the internet is true" - Albert Einstein, 1965'
+	println("I'm correctly formatted")
+	println('"Everything on the internet is true" - Albert Einstein, 1965')
 	println('I\'m out of idea "_"')
-	// "Definitely out \":'(\"" => 'Definitely out ":\'("'
+	println('Definitely out ":\'("')
 }

vlib/v/fmt/tests/string_quotes_input.vv

@@ -3,9 +3,8 @@ fn main() {
 	println('This is correct !')
 	println("It's okay")
 	println('This is "too"')
-	// TODO
-	// 'I\'m not correctly formatted' => "I'm not correctly formatted"
-	// "\"Everything on the internet is true\" - Albert Einstein, 1965" => '"Everything on the internet is true" - Albert Einstein, 1965'
+	println('I\'m correctly formatted')
+	println("\"Everything on the internet is true\" - Albert Einstein, 1965")
 	println('I\'m out of idea "_"')
-	// "Definitely out \":'(\"" => 'Definitely out ":\'("'
+	println("Definitely out \":'(\"")
 }

vlib/v/gen/auto_str_methods.v

@@ -44,7 +44,7 @@ fn (g &Gen) type_to_fmt(typ table.Type) string {
 		[.struct_, .array, .array_fixed, .map, .bool, .enum_, .interface_, .sum_type, .function] {
 		return '%.*s\\000'
 	} else if sym.kind == .string {
-		return "\'%.*s\\000\'"
+		return "'%.*s\\000'"
 	} else if sym.kind in [.f32, .f64] {
 		return '%g\\000' // g removes trailing zeros unlike %f
 	} else if sym.kind == .u64 {

vlib/v/gen/cgen.v

@@ -1438,7 +1438,7 @@ fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type_raw table.Type, expected_t
 
 // cestring returns a V string, properly escaped for embeddeding in a C string literal.
 fn cestring(s string) string {
-	return s.replace('\\', '\\\\').replace('"', "\'")
+	return s.replace('\\', '\\\\').replace('"', "'")
 }
 
 // ctoslit returns a '_SLIT("$s")' call, where s is properly escaped.

vlib/v/scanner/scanner.v

@@ -1154,7 +1154,7 @@ fn (mut s Scanner) ident_char() string {
 		}
 	}
 	// Escapes a `'` character
-	return if c == "\'" {
+	return if c == "'" {
 		'\\' + c
 	} else {
 		c

vlib/vweb/tmpl/tmpl.v

@@ -7,8 +7,8 @@ import os
 import strings
 
 const (
-	str_start = "sb.write(\'"
-	str_end   = "\' ) "
+	str_start = "sb.write('"
+	str_end   = "' ) "
 )
 
 // compile_file compiles the content of a file by the given path as a template
@@ -33,14 +33,14 @@ pub fn compile_template(html_ string, fn_name string) string {
 		h := os.read_file('templates/header.html') or {
 			panic('reading file templates/header.html failed')
 		}
-		header = h.trim_space().replace("\'", '"')
+		header = h.trim_space().replace("'", '"')
 		html = header + html
 	}
 	if os.exists('templates/footer.html') && html.contains('@footer') {
 		f := os.read_file('templates/footer.html') or {
 			panic('reading file templates/footer.html failed')
 		}
-		footer = f.trim_space().replace("\'", '"')
+		footer = f.trim_space().replace("'", '"')
 		html += footer
 	}
 	mut lines := html.split_into_lines()
@@ -81,7 +81,7 @@ _ = footer
 			mut file_content := os.read_file(file_path) or {
 				panic('reading file $file_name failed')
 			}
-			file_content = file_content.replace("\'", '"')
+			file_content = file_content.replace("'", '"')
 			lines2 := file_content.split_into_lines()
 			for l in lines2 {
 				lines.insert(i + 1, l)