v.pref: support a -q option, silencing many repeated messages like the one for v -prod run file.v

vlib/v/builder/cc.v

@@ -65,6 +65,10 @@ fn (mut v Builder) post_process_c_compiler_output(res os.Result) {
 		}
 	}
 	if os.getenv('V_NO_C_ERROR_INFO') != '' {
+		eprintln('> V_NO_C_ERROR_INFO is obsoleted by either setting VQUIET to 1, or by passing `-q` on the command line')
+		exit(1)
+	}
+	if v.pref.is_quiet {
 		exit(1)
 	}
 	verror('

vlib/v/help/build/build.txt

@@ -166,6 +166,14 @@ NB: the build flags are shared with the run command too:
   -translated
     Enable features that are discouraged in regular V code but required for translated V code.
 
+  -q
+    Tell V to be quieter, and to not show many otherwise helpful messages, that only get in your
+    way once you have read them a few dozen times. One example is the notice message, usually
+    shown for `v -prod run file.v`, that says that -prod should not be used with run .
+    Note, this option *does not affect* errors/warnings/notices, just messages that V prints in 
+    order to be more user friendly, in common situations, that are error prone for new users, and
+    that just needlessly take vertical space, once you are well aware of them.
+
   -v
     Enable verbosity in the V compiler while compiling
 

vlib/v/pref/pref.v

@@ -131,6 +131,7 @@ pub mut:
 	is_ios_simulator   bool
 	is_apk             bool     // build as Android .apk format
 	is_help            bool     // -h, -help or --help was passed
+	is_quiet           bool     // do not show the repetitive explanatory messages like the one for `v -prod run file.v` .
 	is_cstrict         bool     // turn on more C warnings; slightly slower
 	eval_argument      string   // `println(2+2)` on `v -e "println(2+2)"`. Note that this souce code, will be evaluated in vsh mode, so 'v -e 'println(ls(".")!)' is valid.
 	test_runner        string   // can be 'simple' (fastest, but much less detailed), 'tap', 'normal'
@@ -309,6 +310,9 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 		res.m64 = true // follow V model by default
 	}
 	res.run_only = os.getenv('VTEST_ONLY_FN').split_any(',')
+	if os.getenv('VQUIET') != '' {
+		res.is_quiet = true
+	}
 	mut command := ''
 	mut command_pos := -1
 
@@ -339,8 +343,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 				target_arch := cmdline.option(current_args, '-arch', '')
 				i++
 				target_arch_kind := arch_from_string(target_arch) or {
-					eprintln('unknown architecture target `${target_arch}`')
+					eprintln_exit('unknown architecture target `${target_arch}`')
-					exit(1)
 				}
 				res.arch = target_arch_kind
 				res.build_options << '${arg} ${target_arch}'
@@ -380,6 +383,13 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 				// Note: help is *very important*, just respond to all variations:
 				res.is_help = true
 			}
+			'-q' {
+				if command_pos != -1 {
+					// a -q flag after a command is for the command, not for v
+					continue
+				}
+				res.is_quiet = true
+			}
 			'-v' {
 				if command_pos != -1 {
 					// a -v flag after the command, is intended for the command, not for V itself
@@ -395,6 +405,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 			}
 			'-progress' {
 				// processed by testing tools in cmd/tools/modules/testing/common.v
+				continue
 			}
 			'-Wimpure-v' {
 				res.warn_impure_v = true
@@ -513,7 +524,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 				res.is_shared = true
 			}
 			'--enable-globals' {
-				eprintln_cond(show_output, '`--enable-globals` flag is deprecated, please use `-enable-globals` instead')
+				eprintln_cond(show_output && !res.is_quiet, '`--enable-globals` flag is deprecated, please use `-enable-globals` instead')
 				res.enable_globals = true
 			}
 			'-enable-globals' {
@@ -704,8 +715,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 				res.skip_warnings = true
 			}
 			'-watch' {
-				eprintln('The -watch option is deprecated. Please use the watch command `v watch file.v` instead.')
+				eprintln_exit('The -watch option is deprecated. Please use the watch command `v watch file.v` instead.')
-				exit(1)
 			}
 			'-print-v-files' {
 				res.print_v_files = true
@@ -721,8 +731,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 						res.output_cross_c = true
 						continue
 					}
-					eprintln('unknown operating system target `${target_os}`')
+					eprintln_exit('unknown operating system target `${target_os}`')
-					exit(1)
 				}
 				if target_os_kind == .wasm32 {
 					res.is_bare = true
@@ -757,11 +766,6 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 				}
 				i++
 			}
-			'-error-limit' {
-				eprintln('Note: the -error-limit option is deprecated, and will be removed in 2023/01/15. Use `-message-limit N` instead.')
-				res.message_limit = cmdline.option(current_args, arg, '5').int()
-				i++
-			}
 			'-message-limit' {
 				res.message_limit = cmdline.option(current_args, arg, '5').int()
 				i++
@@ -804,9 +808,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 				sbackend := cmdline.option(current_args, arg, 'c')
 				res.build_options << '${arg} ${sbackend}'
 				b := backend_from_string(sbackend) or {
-					eprintln('Unknown V backend: ${sbackend}')
+					eprintln_exit('Unknown V backend: ${sbackend}\nValid -backend choices are: c, go, interpret, js, js_node, js_browser, js_freestanding, native, wasm')
-					eprintln('Valid -backend choices are: c, go, interpret, js, js_node, js_browser, js_freestanding, native, wasm')
-					exit(1)
 				}
 				if b.is_js() {
 					res.output_cross_c = true
@@ -833,8 +835,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 				path := cmdline.option(current_args, '-custom-prelude', '')
 				res.build_options << '${arg} ${path}'
 				prelude := os.read_file(path) or {
-					eprintln('cannot open custom prelude file: ${err}')
+					eprintln_exit('cannot open custom prelude file: ${err}')
-					exit(1)
 				}
 				res.custom_prelude = prelude
 				i++
@@ -874,8 +875,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 			}
 			else {
 				if command == 'build' && is_source_file(arg) {
-					eprintln('Use `v ${arg}` instead.')
+					eprintln_exit('Use `v ${arg}` instead.')
-					exit(1)
 				}
 				if arg.len != 0 && arg[0] == `-` {
 					if arg[1..] in pref.list_of_flags_with_param {
@@ -892,8 +892,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 						}
 					} else if is_source_file(command) && is_source_file(arg)
 						&& command !in known_external_commands && res.raw_vsh_tmp_prefix == '' {
-						eprintln('Too many targets. Specify just one target: <target.v|target_directory>.')
+						eprintln_exit('Too many targets. Specify just one target: <target.v|target_directory>.')
-						exit(1)
 					}
 					continue
 				}
@@ -907,8 +906,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 					continue
 				}
 				extension := if command.len == 0 { '' } else { ' for command `${command}`' }
-				eprintln('Unknown argument `${arg}`${extension}')
+				eprintln_exit('Unknown argument `${arg}`${extension}')
-				exit(1)
 			}
 		}
 	}
@@ -919,21 +917,18 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 		res.is_run = true
 	}
 	if command == 'run' && res.is_prod && os.is_atty(1) > 0 {
-		eprintln_cond(show_output, "Note: building an optimized binary takes much longer. It shouldn't be used with `v run`.")
+		eprintln_cond(show_output && !res.is_quiet, "Note: building an optimized binary takes much longer. It shouldn't be used with `v run`.")
-		eprintln_cond(show_output, 'Use `v run` without optimization, or build an optimized binary with -prod first, then run it separately.')
+		eprintln_cond(show_output && !res.is_quiet, 'Use `v run` without optimization, or build an optimized binary with -prod first, then run it separately.')
 	}
 	if res.os in [.browser, .wasi] && res.backend != .wasm {
-		eprintln('OS `${res.os}` forbidden for backends other than wasm')
+		eprintln_exit('OS `${res.os}` forbidden for backends other than wasm')
-		exit(1)
 	}
 	if res.backend == .wasm && res.os !in [.browser, .wasi, ._auto] {
-		eprintln('Native WebAssembly backend OS must be `browser` or `wasi`')
+		eprintln_exit('Native WebAssembly backend OS must be `browser` or `wasi`')
-		exit(1)
 	}
 
 	if command != 'doc' && res.out_name.ends_with('.v') {
-		eprintln('Cannot save output binary in a .v file.')
+		eprintln_exit('Cannot save output binary in a .v file.')
-		exit(1)
 	}
 	if res.fast_math {
 		if res.ccompiler_type == .msvc {
@@ -949,8 +944,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 
 	if res.is_run || res.is_crun {
 		if command_pos + 2 > args.len {
-			eprintln('v run: no v files listed')
+			eprintln_exit('v run: no v files listed')
-			exit(1)
 		}
 		res.path = args[command_pos + 1]
 		res.run_args = args[command_pos + 2..]
@@ -962,14 +956,14 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 		must_exist(res.path)
 		if !res.path.ends_with('.v') && os.is_executable(res.path) && os.is_file(res.path)
 			&& os.is_file(res.path + '.v') {
-			eprintln_cond(show_output, 'It looks like you wanted to run "${res.path}.v", so we went ahead and did that since "${res.path}" is an executable.')
+			eprintln_cond(show_output && !res.is_quiet, 'It looks like you wanted to run "${res.path}.v", so we went ahead and did that since "${res.path}" is an executable.')
 			res.path += '.v'
 		}
 	} else if is_source_file(command) {
 		res.path = command
 	}
 	if !res.is_bare && res.bare_builtin_dir != '' {
-		eprintln_cond(show_output, '`-bare-builtin-dir` must be used with `-freestanding`')
+		eprintln_cond(show_output && !res.is_quiet, '`-bare-builtin-dir` must be used with `-freestanding`')
 	}
 	if command.ends_with('.vsh') || (res.raw_vsh_tmp_prefix != '' && !res.is_run) {
 		// `v build.vsh gcc` is the same as `v run build.vsh gcc`,
@@ -981,8 +975,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 	} else if command == 'interpret' {
 		res.backend = .interpret
 		if command_pos + 2 > args.len {
-			eprintln('v interpret: no v files listed')
+			eprintln_exit('v interpret: no v files listed')
-			exit(1)
 		}
 		res.path = args[command_pos + 1]
 		res.run_args = args[command_pos + 2..]
@@ -991,7 +984,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 			must_exist(res.path)
 			if !res.path.ends_with('.v') && os.is_executable(res.path) && os.is_file(res.path)
 				&& os.is_file(res.path + '.v') {
-				eprintln('It looks like you wanted to run "${res.path}.v", so we went ahead and did that since "${res.path}" is an executable.')
+				eprintln_cond(show_output && !res.is_quiet, 'It looks like you wanted to run "${res.path}.v", so we went ahead and did that since "${res.path}" is an executable.')
 				res.path += '.v'
 			}
 		}
@@ -999,8 +992,7 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 	if command == 'build-module' {
 		res.build_mode = .build_module
 		if command_pos + 1 >= args.len {
-			eprintln('v build-module: no module specified')
+			eprintln_exit('v build-module: no module specified')
-			exit(1)
 		}
 		res.path = args[command_pos + 1]
 	}
@@ -1024,6 +1016,12 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 	return res, command
 }
 
+[noreturn]
+pub fn eprintln_exit(s string) {
+	eprintln(s)
+	exit(1)
+}
+
 pub fn eprintln_cond(condition bool, s string) {
 	if !condition {
 		return
@@ -1090,8 +1088,7 @@ pub fn arch_from_string(arch_str string) !Arch {
 
 fn must_exist(path string) {
 	if !os.exists(path) {
-		eprintln('v expects that `${path}` exists, but it does not')
+		eprintln_exit('v expects that `${path}` exists, but it does not')
-		exit(1)
 	}
 }
 
@@ -1167,9 +1164,6 @@ fn (mut prefs Preferences) parse_define(define string) {
 	if define_parts.len == 1 {
 		prefs.compile_defines << define
 		prefs.compile_defines_all << define
-		if define == 'no_bounds_checking' {
-			prefs.no_bounds_checking = true
-		}
 		return
 	}
 	if define_parts.len == 2 {
@@ -1180,25 +1174,20 @@ fn (mut prefs Preferences) parse_define(define string) {
 				prefs.compile_defines << define_parts[0]
 			}
 			else {
-				println(
+				eprintln_exit(
 					'V error: Unknown define argument value `${define_parts[1]}` for ${define_parts[0]}.' +
 					' Expected `0` or `1`.')
-				exit(1)
 			}
 		}
 		return
 	}
-	println('V error: Unknown define argument: ${define}. Expected at most one `=`.')
+	eprintln_exit('V error: Unknown define argument: ${define}. Expected at most one `=`.')
-	exit(1)
 }
 
 fn (mut prefs Preferences) diagnose_deprecated_defines(define_parts []string) {
-	if define_parts[0] == 'force_embed_file' {
+	// if define_parts[0] == 'no_bounds_checking' {
-		eprintln('`-d force_embed_file` was deprecated in 2022/06/01. Now \$embed_file(file) always embeds the file, unless you pass `-d embed_only_metadata`.')
+	// 	eprintln('`-d no_bounds_checking` was deprecated in 2022/10/30. Use `-no-bounds-checking` instead.')
-	}
+	// }
-	if define_parts[0] == 'no_bounds_checking' {
-		eprintln('`-d no_bounds_checking` was deprecated in 2022/10/30. Use `-no-bounds-checking` instead.')
-	}
 }
 
 pub fn supported_test_runners_list() string {