From 7158a012c391b1f94defee3f470dd1c531f573fb Mon Sep 17 00:00:00 2001
From: joe-conigliaro <joe-conigliaro@users.noreply.github.com>
Date: Mon, 25 Nov 2019 21:48:26 +1100
Subject: [PATCH] compiler: update to get vweb working

---
 vlib/compiler/comptime.v | 25 ++++----------------
 vlib/compiler/parser.v   | 50 ++++++++++++++++++++++++++++++++++++++++
 vlib/vweb/tmpl/tmpl.v    |  2 +-
 3 files changed, 56 insertions(+), 21 deletions(-)

diff --git a/vlib/compiler/comptime.v b/vlib/compiler/comptime.v
index 1fd5c1b847..8478065c3d 100644
--- a/vlib/compiler/comptime.v
+++ b/vlib/compiler/comptime.v
@@ -163,29 +163,14 @@ fn (p mut Parser) comp_time() {
 		p.check(.lpar)
 		p.check(.rpar)
 		v_code := tmpl.compile_template(path)
-		if os.file_exists('.vwebtmpl.v') {
-			os.rm('.vwebtmpl.v')
+		is_strings_imorted := p.import_table.known_import('strings')
+		if !is_strings_imorted {
+			p.register_import('strings', 0) // used by v_code
 		}
-		os.write_file('.vwebtmpl.v', v_code.clone()) // TODO don't need clone, compiler bug
-		p.genln('')
-		// Parse the function and embed resulting C code in current function so that
-		// all variables are available.
-		pos := p.cgen.lines.len - 1
-		mut pp := p.v.new_parser_from_file('.vwebtmpl.v')
-		if !p.pref.is_debug {
-			os.rm('.vwebtmpl.v')
-		}
-		pp.is_vweb = true
-		pp.set_current_fn( p.cur_fn ) // give access too all variables in current function
-		pp.parse(.main)
-		pp.v.add_parser(pp)
-		tmpl_fn_body := p.cgen.lines.slice(pos + 2, p.cgen.lines.len).join('\n').clone()
-		end_pos := tmpl_fn_body.last_index('Builder_str( sb )')  + 19 // TODO
-		p.cgen.lines = p.cgen.lines[..pos]
+		p.import_table.register_used_import('strings')
 		p.genln('/////////////////// tmpl start')
-		p.genln(tmpl_fn_body[..end_pos])
+		p.statements_from_text(v_code, false)
 		p.genln('/////////////////// tmpl end')
-		// `app.vweb.html(index_view())`
 		receiver := p.cur_fn.args[0]
 		dot := if receiver.is_mut { '->' } else { '.' }
 		p.genln('vweb__Context_html($receiver.name $dot vweb, tmpl_res)')
diff --git a/vlib/compiler/parser.v b/vlib/compiler/parser.v
index 792b603d2c..ca718eba5e 100644
--- a/vlib/compiler/parser.v
+++ b/vlib/compiler/parser.v
@@ -89,6 +89,16 @@ const (
 	}
 )
 
+struct ParserState {
+	scanner_text string
+	tokens       []Token
+	token_idx    int
+	tok          TokenKind
+	prev_tok     TokenKind
+	prev_tok2    TokenKind
+	lit          string
+}
+
 // new parser from string. unique id specified in `id`.
 // tip: use a hashing function to auto generate `id` from `text` eg. sha1.hexhash(text)
 fn (v mut V) new_parser_from_string(text string) Parser {
@@ -265,6 +275,34 @@ fn (p &Parser) log(s string) {
 */
 }
 
+pub fn (p mut Parser) save_state() ParserState {
+	return ParserState{
+		scanner_text : p.scanner.text
+		tokens       : p.tokens
+		token_idx    : p.token_idx
+		tok          : p.tok
+		prev_tok     : p.prev_tok
+		prev_tok2    : p.prev_tok2
+		lit          : p.lit
+	}
+}
+
+pub fn (p mut Parser) restore_state(state ParserState) {
+	p.scanner.text = state.scanner_text
+	p.tokens       = state.tokens
+	p.token_idx    = state.token_idx
+	p.tok          = state.tok
+	p.prev_tok     = state.prev_tok
+	p.prev_tok2    = state.prev_tok2
+	p.lit          = state.lit
+}
+
+fn (p mut Parser) clear_state() {
+	p.tokens = []
+	p.token_idx = 0
+	p.scanner.text = ''
+}
+
 pub fn (p mut Parser) add_text(text string) {
 	if p.tokens.len > 1 && p.tokens[p.tokens.len-1].tok == .eof {
 		p.tokens.delete(p.tokens.len-1)
@@ -273,6 +311,18 @@ pub fn (p mut Parser) add_text(text string) {
 	p.scan_tokens()
 }
 
+fn (p mut Parser) statements_from_text(text string, rcbr bool) {
+	saved_state := p.save_state()
+	p.clear_state()
+	p.add_text(text)
+	if rcbr {
+		p.statements()
+	} else {
+		p.statements_no_rcbr()
+	}
+	p.restore_state(saved_state)
+}
+
 fn (p mut Parser) parse(pass Pass) {
 	p.cgen.line = 0
 	p.cgen.file = cescaped_path(os.realpath(p.file_path))
diff --git a/vlib/vweb/tmpl/tmpl.v b/vlib/vweb/tmpl/tmpl.v
index 8db7c8cf3e..aed5e84040 100644
--- a/vlib/vweb/tmpl/tmpl.v
+++ b/vlib/vweb/tmpl/tmpl.v
@@ -28,7 +28,7 @@ pub fn compile_template(path string) string {
 	lines := html.split_into_lines() 
 	mut s := strings.new_builder(1000) 
 	base := path.all_after('/').replace('.html', '')
-	s.writeln('module main import strings fn ${base}_view() string {   // this line will get removed becase only function body is embedded 
+	s.writeln(' 
 mut sb := strings.new_builder(${lines.len * 30})
 header := \'$header\' 
 _ = header