From 4538efd8f4ec0583c2220a8d835757318583ea89 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Thu, 28 Apr 2022 13:15:09 +0300
Subject: [PATCH] eval: small cleanup in the handling of `$if platform {`

---
 vlib/v/eval/eval.v | 10 +++++-----
 vlib/v/eval/expr.v | 35 +++++++++++------------------------
 2 files changed, 16 insertions(+), 29 deletions(-)

diff --git a/vlib/v/eval/eval.v b/vlib/v/eval/eval.v
index 2e27e88268..e64fcdcde4 100644
--- a/vlib/v/eval/eval.v
+++ b/vlib/v/eval/eval.v
@@ -117,7 +117,6 @@ pub fn (mut e Eval) register_symbols(mut files []&ast.File) {
 	for mut file in files {
 		file.idx = e.trace_file_paths.len
 		e.trace_file_paths << file.path
-		// eprintln('registering file: $file.path_base')
 		mod := file.mod.name
 		for mut stmt in file.stmts {
 			if mut stmt is ast.FnDecl {
@@ -205,7 +204,7 @@ pub fn (mut e Eval) register_symbol(stmt ast.Stmt, mod string, file string) {
 								}
 							}
 							else {
-								eprintln('unsupported expression')
+								e.error('unsupported expression')
 							}
 						}
 					}
@@ -223,9 +222,10 @@ pub fn (mut e Eval) register_symbol(stmt ast.Stmt, mod string, file string) {
 
 fn (e Eval) error(msg string) {
 	eprintln('> V interpeter backtrace:')
-	for idx, t in e.back_trace {
-		eprintln('  ${e.trace_file_paths[t.file_idx]}:${t.line + 1}:${e.trace_function_names[t.fn_idx]}')
-		// eprintln('${e.trace_file_paths[t.file_idx]}:${t.line + 1}:$t.fn_idx')
+	for t in e.back_trace {
+		file_path := e.trace_file_paths[t.file_idx] or { t.file_idx.str() }
+		fn_name := e.trace_function_names[t.fn_idx] or { t.fn_idx.str() }
+		eprintln('  $file_path:${t.line + 1}:$fn_name}')
 	}
 	util.verror('interpreter', msg)
 }
diff --git a/vlib/v/eval/expr.v b/vlib/v/eval/expr.v
index 2e78ec5f0a..f6bbf78fe6 100644
--- a/vlib/v/eval/expr.v
+++ b/vlib/v/eval/expr.v
@@ -1,5 +1,6 @@
 module eval
 
+import v.pref
 import v.ast
 import v.util
 import math
@@ -134,30 +135,16 @@ pub fn (mut e Eval) expr(expr ast.Expr, expecting ast.Type) Object {
 						do_if = true
 					} else {
 						if branch.cond is ast.Ident {
-							match branch.cond.name {
-								'windows' {
-									do_if = e.pref.os == .windows
-								}
-								'macos' {
-									do_if = e.pref.os == .macos
-								}
-								'linux' {
-									do_if = e.pref.os == .linux
-								}
-								'android' {
-									do_if = e.pref.os == .android
-								}
-								'freebsd' {
-									do_if = e.pref.os == .freebsd
-								}
-								'openbsd' {
-									do_if = e.pref.os == .openbsd
-								}
-								'prealloc' {
-									do_if = e.pref.prealloc
-								}
-								else {
-									e.error('unknown compile time if: $branch.cond.name')
+							if known_os := pref.os_from_string(branch.cond.name) {
+								do_if = e.pref.os == known_os
+							} else {
+								match branch.cond.name {
+									'prealloc' {
+										do_if = e.pref.prealloc
+									}
+									else {
+										e.error('unknown compile time if: $branch.cond.name')
+									}
 								}
 							}
 						} else if branch.cond is ast.PostfixExpr {