From b1fa0d25f07682a76fb41d436a0a85185b76d018 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 13 Nov 2019 21:47:05 +0300
Subject: [PATCH] foo()? syntax

---
 vlib/compiler/comptime.v          |  6 ++++--
 vlib/compiler/expression.v        | 24 +++++++++++++++++++-----
 vlib/compiler/gen_c.v             |  4 ++--
 vlib/compiler/main.v              |  2 +-
 vlib/compiler/tests/option_test.v |  8 ++++++++
 5 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/vlib/compiler/comptime.v b/vlib/compiler/comptime.v
index a9c7824e7b..01c3c6ceb5 100644
--- a/vlib/compiler/comptime.v
+++ b/vlib/compiler/comptime.v
@@ -103,7 +103,9 @@ fn (p mut Parser) comp_time() {
 			else_returns := p.returns
 			p.returns = if_returns && else_returns
 			//p.gen('/* returns $p.returns */')
-		}
+		} else if p.tok == .key_else {
+			p.error('use `$' + 'else` instead of `else` in comptime if statements')
+		}	
 	}
 	else if p.tok == .key_for {
 		p.next()
@@ -234,7 +236,7 @@ fn (p mut Parser) chash() {
 			p.cgen.includes << '#$hash'
 		}
 	}
-	// Don't parse a non-JS V file (`#-js` flag)
+	//// Don't parse a non-JS V file (`#-js` flag)
 	else if hash == '-js'  {
 		$if js {
 			for p.tok != .eof {
diff --git a/vlib/compiler/expression.v b/vlib/compiler/expression.v
index eb5885a476..234467fbf2 100644
--- a/vlib/compiler/expression.v
+++ b/vlib/compiler/expression.v
@@ -221,8 +221,6 @@ fn (p mut Parser) name_expr() string {
 		!p.table.known_fn(name) && !p.table.known_const(name) && !is_c
 	{
 		name = p.prepend_mod(name)
-	} else {
-		//println('$name')
 	}	
 	// re-check
 	if p.known_var_check_new_var(name) {
@@ -331,13 +329,29 @@ fn (p mut Parser) name_expr() string {
 	f = new_f
 
 	// optional function call `function() or {}`, no return assignment
-    is_or_else := p.tok == .key_orelse
-    if !p.is_var_decl && is_or_else {
+	is_or_else := p.tok == .key_orelse
+	if p.tok == .question {
+		// `files := os.ls('.')?`
+		if p.cur_fn.name != 'main__main' {
+			p.error('`func()?` syntax can only be used inside `fn main()` for now')
+		}	
+		p.next()
+		tmp := p.get_tmp()
+		p.cgen.set_placeholder(fn_call_ph, '$f.typ $tmp = ')
+		p.genln(';')
+		p.genln('if (!${tmp}.ok) v_panic(${tmp}.error);')
+		typ := f.typ[7..] // option_xxx
+		p.gen('*($typ*) ${tmp}.data;')
+		return typ
+	}	
+	else if !p.is_var_decl && is_or_else {
 		f.typ = p.gen_handle_option_or_else(f.typ, '', fn_call_ph)
+		p.print_tok()
 	}
-    else if !p.is_var_decl && !is_or_else && !p.inside_return_expr &&
+    else if !p.is_var_decl && !is_or_else  && !p.inside_return_expr &&
 		f.typ.starts_with('Option_') {
         opt_type := f.typ[7..]
+       p.print_tok()
         p.error('unhandled option type: `?$opt_type`')
     }
 
diff --git a/vlib/compiler/gen_c.v b/vlib/compiler/gen_c.v
index 59f4b1424a..eaf059e265 100644
--- a/vlib/compiler/gen_c.v
+++ b/vlib/compiler/gen_c.v
@@ -129,11 +129,11 @@ fn (p mut Parser) gen_handle_option_or_else(_typ, name string, fn_call_ph int) s
 		expr_line := p.cgen.lines[p.cgen.lines.len-2]
 		last_expr := expr_line[last_ph..]
 		p.cgen.lines[p.cgen.lines.len-2]  = ''
-		p.genln('if (!$tmp .ok) {')
+		p.genln('if (!${tmp}.ok) {')
 		p.genln('$name = $last_expr;')
 		p.genln('}')
 	} else if is_assign {
-		p.genln('$name = *($typ*) $tmp . data;')
+		p.genln('$name = *($typ*)${tmp}.data;')
 	}
 	if !p.returns && last_typ != typ && is_assign && p.prev_tok2 != .key_continue && p.prev_tok2 != .key_break {
 		p.error_with_token_index('`or` block must provide a default value or return/exit/continue/break/panic', or_tok_idx)
diff --git a/vlib/compiler/main.v b/vlib/compiler/main.v
index e2e0482773..ce06cba24c 100644
--- a/vlib/compiler/main.v
+++ b/vlib/compiler/main.v
@@ -892,7 +892,7 @@ pub fn new_v(args[]string) &V {
 	//println('VROOT=$vroot')
 	// v.exe's parent directory should contain vlib
 	if !os.dir_exists(vroot) || !os.dir_exists(vroot + '/vlib/builtin') {
-		println('vlib not found, downloading it...')
+		//println('vlib not found, downloading it...')
 		/*
 		ret := os.system('git clone --depth=1 https://github.com/vlang/v .')
 		if ret != 0 {
diff --git a/vlib/compiler/tests/option_test.v b/vlib/compiler/tests/option_test.v
index f9250ad38a..c6961d0450 100644
--- a/vlib/compiler/tests/option_test.v
+++ b/vlib/compiler/tests/option_test.v
@@ -70,3 +70,11 @@ fn test_opt_default() {
 	}
 	assert a == 'default'
 }
+
+fn foo_ok() ?int {
+	return 777
+}	
+
+fn test_q() {
+	//assert foo_ok()? == true
+}