From fa4a45d37f383d1fdbf7059738b62fe3fd7b68fe Mon Sep 17 00:00:00 2001
From: shove <shove@163.com>
Date: Thu, 3 Nov 2022 19:32:07 +0800
Subject: [PATCH] all: make fmt support two kinds of interpolation at the same
 time. (#16308)

---
 vlib/v/ast/ast.v         | 1 +
 vlib/v/ast/str.v         | 6 ++++--
 vlib/v/fmt/fmt.v         | 4 +++-
 vlib/v/parser/parser.v   | 8 ++++++--
 vlib/v/scanner/scanner.v | 2 +-
 vlib/v/token/token.v     | 8 ++++++--
 6 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 5f6eea6276..22229371ba 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -216,6 +216,7 @@ pub:
 	fills      []bool
 	fmt_poss   []token.Pos
 	pos        token.Pos
+	has_dollar []bool // two interpolation ways are temporarily supported
 pub mut:
 	exprs      []Expr
 	expr_types []Type
diff --git a/vlib/v/ast/str.v b/vlib/v/ast/str.v
index 9dd9c9ee33..879bf2442b 100644
--- a/vlib/v/ast/str.v
+++ b/vlib/v/ast/str.v
@@ -230,7 +230,7 @@ pub fn (lit &StringInterLiteral) get_fspec_braces(i int) (string, bool) {
 	needs_fspec := lit.need_fmts[i] || lit.pluss[i]
 		|| (lit.fills[i] && lit.fwidths[i] >= 0) || lit.fwidths[i] != 0
 		|| lit.precisions[i] != 987698
-	mut needs_braces := needs_fspec
+	mut needs_braces := !lit.has_dollar[i] || needs_fspec
 	sx := lit.exprs[i].str()
 	if sx.contains(r'"') || sx.contains(r"'") {
 		needs_braces = true
@@ -480,7 +480,9 @@ pub fn (x Expr) str() string {
 				if i >= x.exprs.len {
 					break
 				}
-				res.write_string('$')
+				if x.has_dollar[i] {
+					res.write_string('$')
+				}
 				fspec_str, needs_braces := x.get_fspec_braces(i)
 				if needs_braces {
 					res.write_string('{')
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index 4b21b7bb9b..d1a3630886 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -2684,7 +2684,9 @@ pub fn (mut f Fmt) string_inter_literal(node ast.StringInterLiteral) {
 		if i >= node.exprs.len {
 			break
 		}
-		f.write('$')
+		if node.has_dollar[i] {
+			f.write('$')
+		}
 		fspec_str, needs_braces := node.get_fspec_braces(i)
 		if needs_braces {
 			f.write('{')
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index 405b603904..19c067aa13 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -3056,7 +3056,7 @@ fn (mut p Parser) string_expr() ast.Expr {
 	val := p.tok.lit
 	mut pos := p.tok.pos()
 	pos.last_line = pos.line_nr + val.count('\n')
-	if p.peek_tok.kind != .str_dollar {
+	if p.peek_tok.kind != .str_dollar && p.peek_tok.kind != .str_lcbr {
 		p.next()
 		p.filter_string_vet_errors(pos)
 		node = ast.StringLiteral{
@@ -3076,14 +3076,16 @@ fn (mut p Parser) string_expr() ast.Expr {
 	mut fills := []bool{}
 	mut fmts := []u8{}
 	mut fposs := []token.Pos{}
+	mut has_dollar := []bool{}
 	// Handle $ interpolation
 	p.inside_str_interp = true
 	for p.tok.kind == .string {
 		vals << p.tok.lit
 		p.next()
-		if p.tok.kind != .str_dollar {
+		if p.tok.kind != .str_dollar && p.tok.kind != .str_lcbr {
 			break
 		}
+		has_dollar_ := p.tok.kind == .str_dollar
 		p.next()
 		exprs << p.expr(0)
 		mut has_fmt := false
@@ -3136,6 +3138,7 @@ fn (mut p Parser) string_expr() ast.Expr {
 		fmts << fmt
 		fills << fill
 		fposs << p.prev_tok.pos()
+		has_dollar << has_dollar_
 	}
 	pos = pos.extend(p.prev_tok.pos())
 	p.filter_string_vet_errors(pos)
@@ -3150,6 +3153,7 @@ fn (mut p Parser) string_expr() ast.Expr {
 		fmts: fmts
 		fmt_poss: fposs
 		pos: pos
+		has_dollar: has_dollar
 	}
 	// need_fmts: prelimery - until checker finds out if really needed
 	p.inside_str_interp = false
diff --git a/vlib/v/scanner/scanner.v b/vlib/v/scanner/scanner.v
index e5acbbeb83..5d0a0aaca0 100644
--- a/vlib/v/scanner/scanner.v
+++ b/vlib/v/scanner/scanner.v
@@ -813,7 +813,7 @@ fn (mut s Scanner) text_scan() token.Token {
 					if !s.is_inside_interpolation && !next_char.is_space() && next_char != `}`
 						&& prev_char !in [`$`, `{`] {
 						s.is_inside_interpolation = true
-						return s.new_token(.str_dollar, '', 1)
+						return s.new_token(.str_lcbr, '', 1)
 					}
 					if s.is_inside_interpolation && prev_char == `$` {
 						// Skip { in `${` in strings
diff --git a/vlib/v/token/token.v b/vlib/v/token/token.v
index 8f0a221b11..4b82f25e84 100644
--- a/vlib/v/token/token.v
+++ b/vlib/v/token/token.v
@@ -46,7 +46,8 @@ pub enum Kind {
 	hash // #
 	dollar // $
 	at // @
-	str_dollar
+	str_dollar // ${} or $, old interpolation
+	str_lcbr // {interpolation
 	left_shift // <<
 	right_shift // >>
 	unsigned_right_shift // >>>
@@ -269,7 +270,8 @@ fn build_token_str() []string {
 	s[Kind.nl] = 'NLL'
 	s[Kind.dollar] = '$'
 	s[Kind.at] = '@'
-	s[Kind.str_dollar] = '$2'
+	s[Kind.str_dollar] = 'string interpolation1'
+	s[Kind.str_lcbr] = 'string interpolation2'
 	s[Kind.key_assert] = 'assert'
 	s[Kind.key_struct] = 'struct'
 	s[Kind.key_if] = 'if'
@@ -539,6 +541,7 @@ pub fn kind_to_string(k Kind) string {
 		.dollar { 'dollar' }
 		.at { 'at' }
 		.str_dollar { 'str_dollar' }
+		.str_lcbr { 'str_lcbr' }
 		.left_shift { 'left_shift' }
 		.right_shift { 'right_shift' }
 		.unsigned_right_shift { 'unsigned_right_shift' }
@@ -660,6 +663,7 @@ pub fn kind_from_string(s string) !Kind {
 		'dollar' { .dollar }
 		'at' { .at }
 		'str_dollar' { .str_dollar }
+		'str_lcbr' { .str_lcbr }
 		'left_shift' { .left_shift }
 		'right_shift' { .right_shift }
 		'unsigned_right_shift' { .unsigned_right_shift }