compiler: fix MSVC flag parsing

compiler/msvc.v

@@ -204,6 +204,11 @@ fn find_msvc() ?MsvcResult {
 	}
 }
 
+struct ParsedFlag {
+	f string
+	arg string
+}
+
 pub fn (v mut V) cc_msvc() { 
 	r := find_msvc() or {
 		// TODO: code reuse
@@ -296,31 +301,74 @@ pub fn (v mut V) cc_msvc() {
 	// this is a hack to try and support -l -L and object files
 	// passed on the command line
 	for f in v.table.flags {
-		// We need to see if the flag contains -l
-		// -l isnt recognised and these libs will be passed straight to the linker
-		// by the compiler
-		if f.starts_with('-l') {
-			lib_base := f.right(2).trim_space()
+		// People like to put multiple flags per line (which really complicates things)
+		// ...so we need to handle that
+		mut rest := f
 
-			if lib_base.ends_with('.dll') {
-				panic('MSVC cannot link against a dll (`#flag -l $lib_base`)')
+		mut flags := []ParsedFlag{}
+		for {
+			mut base := rest
+
+			fl := if rest.starts_with('-') {
+				base = rest.right(2).trim_space()
+				rest.left(2)
+			} else {
+				''
 			}
 
-			// MSVC has no method of linking against a .dll
-			// TODO: we should look for .defs aswell
-			lib_lib := lib_base + '.lib'
-			real_libs << lib_lib
-		} 
-		else if f.starts_with('-L') {
-			lib_paths << f.right(2).trim_space()
+			// Which ever one of these is lowest we use
+			// TODO: we really shouldnt support all of these cmon
+			mut lowest := base.index('-')
+			for x in [base.index(' '), base.index(',')] {
+				if (x < lowest && x != -1) || lowest == -1 {
+					lowest = x
+				}
+			}
+			arg := if lowest != -1 {
+				rest = base.right(lowest).trim_space().trim(`,`)
+				base.left(lowest).trim_space().trim(`,`)
+			} else {
+				rest = ''
+				base.trim_space()
+			}
+
+			flags << ParsedFlag {
+				fl, arg
+			}
+
+			if rest.len == 0 {
+				break
+			}
 		}
-		else if f.ends_with('.o') {
-			// msvc expects .obj not .o
-			other_flags << f + 'bj'
-		} 
-		else {
-			other_flags << f
+
+		for flag in flags {
+			fl := flag.f
+			arg := flag.arg
+			// We need to see if the flag contains -l
+			// -l isnt recognised and these libs will be passed straight to the linker
+			// by the compiler
+			if fl == '-l' {
+				if arg.ends_with('.dll') {
+					panic('MSVC cannot link against a dll (`#flag -l $arg`)')
+				}
+
+				// MSVC has no method of linking against a .dll
+				// TODO: we should look for .defs aswell
+				lib_lib := arg + '.lib'
+				real_libs << lib_lib
+			} 
+			else if fl == '-L' {
+				lib_paths << f.right(2).trim_space()
+			}
+			else if arg.ends_with('.o') {
+				// msvc expects .obj not .o
+				other_flags << arg + 'bj'
+			} 
+			else {
+				other_flags << arg
+			}
 		}
+		
 	}
 
 	// Include the base paths
@@ -369,9 +417,10 @@ pub fn (v mut V) cc_msvc() {
 
 	if !v.pref.is_debug && v.out_name_c != 'v.c' && v.out_name_c != 'v_macos.c' {
 		os.rm('.$v.out_name_c')
-		os.rm('$out_name_obj')
 	}
 
+	// Always remove the object file - it is completely unnecessary
+	os.rm('$out_name_obj')
 }
 
 fn build_thirdparty_obj_file_with_msvc(flag string) {

compiler/tests/msvc_test.v

@@ -0,0 +1,49 @@
+fn test_flag_parsing() {
+	mut rest := '-lGlfw -f gl2,-ltest_nice_meme,-l cc,-Ldl test.o a.o ' //, whatever.o'
+	result := ['-l', 'Glfw', 
+			   '-f', 'gl2', 
+			   '-l', 'test_nice_meme', 
+			   '-l', 'cc',
+			   '-L', 'dl',
+			   '', 'test.o',
+			   '', 'a.o']
+
+	mut flags := []string
+	for {
+		mut base := rest
+
+		fl := if rest.starts_with('-') {
+			base = rest.right(2).trim_space()
+			rest.left(2)
+		} else {
+			''
+		}
+
+		// Which ever one of these is lowest we use
+		// TODO: we really shouldnt support all of these cmon
+		mut lowest := base.index('-')
+		for x in [base.index(' '), base.index(',')] {
+			if (x < lowest && x != -1) || lowest == -1 {
+				lowest = x
+			}
+		}
+		arg := if lowest != -1 {
+			rest = base.right(lowest).trim_space().trim(`,`)
+			base.left(lowest).trim_space().trim(`,`)
+		} else {
+			rest = ''
+			base.trim_space()
+		}
+
+		flags << fl
+		flags << arg
+
+		if rest.len == 0 {
+			break
+		}
+	}
+
+	for i, f in flags {
+		assert f == result[i] 
+	}
+}