GNU Octave is used in classrooms, research groups and engineering teams around the world, so a function’s argument explanations often travel farther than the developer who wrote them. This guide shows how to make GNU Octave inputParser interfaces understandable across languages while keeping the executable contract correct. It concentrates on required and optional arguments, named parameters, switches, matching rules, diagnostics and safe testing.
People searching for Octave inputParser examples, addSwitch syntax, addParameter validation, PartialMatching, KeepUnmatched, Results or how to translate function error messages usually need two things at once: a runnable explanation of the parser and a clear account of which words may be localized. The names in a function call are not automatically synonyms for translated captions. A language edition of a guide must not promise that a different command spelling will work.
Work from one read-only example, inspect the parser’s result structure, and then test invalid calls deliberately. The practical sequence here runs from basic invocation through ambiguous arguments, multilingual help and version-aware release testing. It keeps GNU Octave’s documented behavior separate from similar-looking MATLAB interfaces and from operating-system command-line options.
Quick answer
- GNU Octave inputParser handles function inputs, not external shell commands.
- Keep executable parameter and switch names exactly as declared.
- Separate required, optional, named and switch arguments.
- Know the consequences of matching and unmatched-value settings.
- Localize explanations, verify errors and compare numerical results across languages.
Read-only GNU Octave inputParser example
function settings = preview_inputs (samples, varargin)
p = inputParser ();
p.FunctionName = "preview_inputs";
p.PartialMatching = false;
p.KeepUnmatched = false;
p.addRequired ("samples", @(x) isnumeric (x) && isvector (x));
p.addParameter ("mode", "summary", @(x) ischar (x) && any (strcmp (x, {"summary", "count"})));
p.addSwitch ("verbose");
p.parse (samples, varargin{:});
settings = p.Results;
endfunction
## preview_inputs ([2, 4, 6], "mode", "count", "verbose")
## preview_inputs ([2, 4, 6])The example returns a structure only; it does not modify a file or a dataset. It demonstrates the documented addSwitch form, an explicitly selected matching policy and a small validator. Run it in a disposable session using your supported GNU Octave release. The word mode is an executable parameter name; a translated label in a guide is not a substitute for that spelling.
What GNU Octave inputParser actually parses
GNU Octave inputParser is designed for arguments to functions. Its documented scheme includes required inputs, optional positional inputs, name-value parameters and switch options. The structure of those arguments determines what a caller must write, and the parser’s Results tell the function what was accepted. Translation starts by respecting that structure, not by rewriting tokens to make them resemble ordinary speech. The distinction is especially useful when a tutorial will be copied into scripts or shared in multilingual classes.
Function inputs differ from command-line flags
The inputs passed through varargin to a user function are not automatically the same as arguments that launched the Octave executable.
A tutorial that blurs these two layers can promise options that Octave itself has never recognized.
Demonstrate a function call in the interpreter and a shell invocation as separate examples, naming the interpreter of each token.
Create the parser before using it
Calling inputParser creates the object that holds the argument scheme, settings and parsed results.
A partial snippet that starts with p.parse but never declares p is not a useful beginner example.
Include a whole function, from parser creation to the final returned structure, so readers can reproduce every step.
Add required positional values
addRequired defines a mandatory function input and can attach a validator to enforce an expected type.
Translating an identifier into a different variable name while leaving references unchanged breaks code rather than improving understanding.
Keep the declared identifier consistent and show one accepted value, one omitted value and one rejected value.
Understand optional positional arguments
addOptional provides a default for an argument supplied by position before the named argument portion.
An explanation that calls every optional value a switch makes valid invocation order hard to predict.
Teach what the position means, then show how the call behaves when that position is omitted.
Treat named parameters as pairs
addParameter defines a name and a value, with a default when callers leave the pair out.
A translated human label may look like a valid parameter even though the parser knows only the declared name.
Print the executable parameter name unchanged and give a short translated description beside it.
Know what an addSwitch option means
The GNU Octave inputParser documentation includes addSwitch, used for a flag-style argument that is present or absent.
Assuming every named option requires a following value can shift the positions of subsequent inputs.
Test the function with and without the switch, then inspect its resulting logical behavior.
Required then optional then named
Required inputs come first, then optional positional inputs, followed by parameters and switches that can be mixed.
A multilingual quick-start reordered for readability can become a syntactically invalid sample.
Write the invocation with visibly grouped arguments and test a deliberate ordering violation to show the boundary.
Read values from Results
After parsing, the Results structure contains the recognized inputs that the function uses.
A documentation editor may change a field reference to a translated display word and inadvertently produce an invalid expression.
Keep field names in code formatting and check the actual stored value in a read-only session.
Inspect UsingDefaults
UsingDefaults records which argument names received defaults in the parse rather than values supplied by the caller.
Students sometimes mistake a default for a value that the parser somehow inferred from surrounding text.
Compare an explicit option with a defaulted option and ask students to describe the provenance of the final value.
InputParser is not a language engine
The parser does not automatically translate function prompts, filenames or numerical result messages for different locales.
A guide that suggests automatic internationalization creates false expectations about built-in behavior.
Make a separate list of translatable explanations, executable identifiers, numeric rules and output strings.
Matching rules, switches and ambiguous inputs
Small-looking parser settings can shape the public API. Short names, case differences and unmatched arguments may be convenient in a local script, but they are not always wise for reusable teaching materials or a library installed in many countries. GNU Octave documents PartialMatching and KeepUnmatched, as well as a StructExpand option. Understanding these rules is essential before a translated guide advises readers to type a shortened name or supply configuration in a structure.
PartialMatching permits prefixes
When enabled, a shortened parameter or switch name may match a uniquely identifiable declared option.
A guide that teaches prefixes as stable spellings can become inaccurate after another option shares the prefix.
Add a deliberately similar second parameter in a test branch and check whether the old abbreviation remains unambiguous.
Choose exact matches for public examples
The shortest runnable command is not always the safest one for long-lived scripts and printed handouts.
A prefix copied by hundreds of students can become a maintenance problem when the function grows.
Show the complete parameter name and state the documented matching policy before discussing abbreviations.
CaseSensitive affects recognition
A parser may treat names differently depending on its CaseSensitive setting, which GNU Octave documents.
Translators may assume that letters with different case are interchangeable because the prose uses them casually.
Test the exact key, its lowercase form and an uppercase variant, and publish what your function actually accepts.
KeepUnmatched requires care
When KeepUnmatched is enabled, unrecognized named inputs can be preserved rather than rejected immediately.
A typo that enters Unmatched can pass unnoticed if the function never examines that structure.
Document why unknown options are accepted and verify that a separate validation step checks their meaning.
Unknown switches are tricky
GNU Octave treats unmatched arguments conservatively because an unknown token could represent either a switch or a parameter.
Allowing unmatched names does not prove that a standalone unknown flag will behave as a recognized switch.
Test an unknown name with and without a value and explain which invocation is supported.
StructExpand changes input presentation
StructExpand controls whether structure data can be expanded into parameter-value entries during parsing.
A localized example showing a struct when the feature is disabled can confuse students about accepted syntax.
Check the property before offering structured configuration as an alternative calling style.
Switches can appear among parameters
After positional inputs, switch options and name-value parameters can be mixed in the documented Octave scheme.
A beginner who always places all switches first may infer a restriction that does not exist.
Demonstrate two valid orders of the same switch and parameter without changing the resulting computation.
A switch does not take a caption value
The presence of a switch conveys a Boolean-style choice; the translated explanation is not an additional argument.
Showing a phrase such as ‘verbose yes’ without verifying syntax may teach an invalid call.
Explain the option in ordinary language and then keep the actual input sequence exact.
Validators still control values
Even recognized parameter names can fail a validator because their supplied values have the wrong class or range.
A broad translation like ‘unknown option’ misdiagnoses a perfectly recognized name with invalid content.
Use separate examples for unrecognized names and invalid values, each with a precise repair action.
Defaults and switches can coexist
A function may use defaulted named settings and presence-based switches in the same invocation.
Readers can lose track of which values came from explicit arguments and which from default logic.
Print Results and UsingDefaults in the example walkthrough, then compare calls that differ by one switch.
Translate guidance while protecting numerical meaning
Scientific users need consistency across language editions more than they need every visible character converted. A label, a value, a unit, a parameter key and an error category perform different jobs. The aim is to reduce the work required to understand a function without altering its measurements or silently changing an experiment. When a term is difficult to translate, a short explanation tied to a runnable example often works better than an isolated dictionary equivalent.
Separate prose from executable names
A readable explanation can translate ‘tolerance’ as a concept while the function still expects its declared key.
Renaming executable identifiers in half a tutorial leaves mismatched code and documentation.
Use a term table linking each stable parameter to one precise human description and one tested example.
Avoid translating literal syntax
Quotes, parentheses, commas, operators and identifier spelling are part of the runnable expression.
A content editor may substitute smart punctuation or decorative marks that readers copy as code.
Publish code in literal formatting and paste it back into a supported GNU Octave interpreter.
Preserve numeric arrays
The contents, shapes and ordering of numeric arrays are scientific inputs, not human-readable labels to rewrite.
Changing array notation for stylistic reasons may create different matrices or alter dimensions.
Use a small matrix and vector with expected sizes, then verify them after every translated example.
Respect decimal representation
A language may normally use decimal commas, while executable numeric expressions have their own grammar.
Converting 1.5 into a locale-formatted phrase inside code may change syntax or interpretation.
Explain decimal convention in prose and keep the exact numeric example runnable.
Keep units explicit
Values without clear units can mislead users even when the spelling and grammar are natural.
A translated ‘rate’ that changes seconds to minutes changes the interpretation of experimental results.
Attach units to examples and have a domain reviewer check whether every conversion is intended.
Check accepted string types
Some validators accept character arrays while others may accept different kinds of text values.
A guide that says ‘enter a string’ may promise an unsupported type in the targeted GNU Octave release.
Show actual accepted input types and distinguish reader text from exact runtime type terminology.
Use Unicode text as test data
Readers across writing systems may supply non-ASCII labels, filenames or notes.
Passing parsing tests with English-only text does not show that downstream files and fonts handle other scripts.
Use disposable labels in multiple scripts, then inspect every output path where they are stored or rendered.
Review right-to-left examples
Arabic or Hebrew prose can wrap around Latin-script parameter names and numerical arrays in confusing ways.
A screenshot may conceal copy-and-paste errors caused by unexpected bidirectional rendering.
Test the live display and selected text, not just an exported image of the page.
Protect file and path identity
A localized explanation of a path is not permission to translate the path components themselves.
Changing the text of a real filename in an example can make a tutorial point to a file that does not exist.
Keep paths literal in code, use disposable fixtures and explain where readers should substitute their own files.
Keep language selection separate
An application may accept a language parameter for its own messages, but this does not redefine inputParser behavior.
Readers might think changing a locale option changes parameter names, numeric operators or the parser’s internal errors.
State exactly which messages the application controls, and compare structured results across the supported locales.
Build trustworthy diagnostics, exercises and releases
Good localization gives readers a way to recover from failure. A parser may reject a wrong type, complain about an ambiguous name, or accept an argument that later code cannot use. Those are not identical events. A useful guide separates them, shows a corrected invocation and makes the boundary between the Octave runtime and application-owned wording visible. Release testing should cover all target languages without pretending a translated page is evidence that the function itself works.
Distinguish name and value errors
An unknown key is a different problem from a recognized key whose value violates its validator.
The message ‘invalid argument’ can be accurate yet too vague for a beginner to fix.
Show the recognized names for one error and the accepted value type for the other.
Do not hide error context
Wrapping every failure with one translated sentence can erase function identity and debugging details.
Support staff then cannot reproduce the report or recognize a regression from a real parameter change.
Keep the technical category and add a short human explanation only for cases the wrapper understands.
Use FunctionName meaningfully
Setting FunctionName can identify the function in parser diagnostics and improve a shared support transcript.
A translated explanation without context may look identical across unrelated utilities in a toolbox.
Keep the real function name in the message and explain the failed condition in reader-friendly language.
Never expose sensitive arguments
Debug output sometimes prints input values including private file paths or user identifiers.
A multilingual error posted publicly can leak the same data in every language.
Use dummy paths and redact sensitive tokens before copying logs into help pages or support tickets.
Teach success and failure together
A perfect demonstration does not explain what happens when the next learner mistypes the parameter name.
Students may understand a printed result but still be unable to diagnose a rejected call.
For each major parameter, include one valid and one invalid invocation with a precise correction.
Use a read-only preview
A simple function that returns its parsed settings is safer than a tutorial that changes research files.
Users exploring an unfamiliar programming language should not need to risk a production workspace.
Make the primary demo return a structure, then integrate it into real processing only after validation.
Record the tested Octave version
GNU Octave documentation describes specific releases, and behavior may evolve over time.
A reader using an older installation might not reproduce every property or example.
State the tested version and refer readers to the matching manual rather than assuming universal parity.
Do not assume MATLAB equivalence
Octave and MATLAB may share method names while differing in implementation details or available features such as documented switches.
Copying a MATLAB tutorial verbatim can create a credible-looking but incorrect Octave guide.
Verify every option and demonstration against the official Octave manual and an Octave runtime.
Review help as an interface
Function comments and error descriptions are part of what users experience, even when the code runs correctly.
A translator working without a sample invocation may choose a term that misstates the required argument.
Give language reviewers the parameter table, expected values and examples before approving the translation.
Preserve behavior across languages
A translated help page should not produce a different numerical answer from its source-language counterpart.
A change in defaults or argument order is an API modification disguised as documentation work.
Use fixed test vectors and compare Results, calculations and intended error categories in every language.
Twelve realistic troubleshooting and teaching situations
International usage raises questions that do not appear in a single perfect example. These cases distinguish what the parser accepts from what a translated handout claims. The last sentence of each case gives a reproducible check that a reader, teacher or maintainer can perform without production data.
A shared statistics course
Students use Octave to summarize a fixed numeric vector. Their instructor wants explanations in English and Indonesian without maintaining two versions of the function.
Publish parallel guidance with identical literal function calls and translated descriptions of each stable argument name.
Give both groups the same vector and compare results before moving to a more realistic dataset.
A misspelled parameter is accepted into Unmatched
A script enables KeepUnmatched to forward extra parameters. A learner types ‘tolerence’ and assumes the tool applied the intended tolerance.
Teach how Unmatched works and add an explicit check before calling downstream computation rather than silently continuing.
Run the typo with and without KeepUnmatched, recording exactly where and when it is rejected.
A bilingual help page relies on abbreviations
A Japanese handout shows shortened parameter names because the examples fit neatly on one printed line.
Use complete keys in code, allowing the explanatory text to wrap instead of shortening the public API.
Add a new parameter that shares a prefix and demonstrate why an abbreviation can become ambiguous.
A verbose switch is misread
A translated paragraph describes verbose output as a yes-or-no value, and a student supplies an extra true token after addSwitch.
Distinguish a presence-based switch from a named parameter that expects a value; show only the actual accepted invocation.
Inspect Results with the switch present and absent, and compare the behavior of the extra token.
A data processing package travels internationally
A laboratory publishes an Octave toolbox for research collaborators with different local keyboard layouts.
Preserve identifiers, store Unicode text reliably and check copying commands from documentation instead of changing keyboard-dependent code syntax.
Ask reviewers in each locale to run one example and one deliberate error and record the actual results.
A course page uses smart quotes
An editorial system replaces the literal quotation marks in GNU Octave examples with curved punctuation.
Store runnable examples in fenced or preformatted code, and teach translators not to alter code typography.
Copy the published sample into a clean interpreter and verify it behaves like the tested source.
A function has optional positional text
An optional path argument and a named ‘type’ parameter both accept text, making a particular invocation hard to read.
Provide complete examples using unambiguous values and explain how required, optional and named phases are recognized.
Try one invocation for each ambiguous boundary and report which is valid in the documented version.
A numerical table is translated
A scientific manual uses locale-specific decimal conventions while embedding executable GNU Octave matrices.
Separate typeset human numbers from actual numeric literals in code; preserve scientific units and array dimensions.
Run the code in both language editions and compare values, shapes and the printed table header separately.
An accessibility review finds a problem
The explanation of a validation error appears only in an image, leaving screen-reader users unable to locate its parameter.
Replace screenshot-only guidance with searchable error text, a copyable sample call and an explicit corrected version.
Have a reviewer navigate the documentation by headings and reproduce the repair without inspecting an image.
A release adds an additional switch
Developers add a switch to show detailed diagnostic output, but a translated help page still lists only the former parameters.
Require a translation review when the parser scheme changes, including updates to tables, examples and exercises.
Compare the parser inventory with documentation before tagging the release.
An Arabic page displays reordered tokens
An Arabic tutorial interleaves right-to-left text and left-to-right identifiers in a single paragraph, confusing punctuation and order.
Set language direction for prose and isolate executable snippets in code formatting with their original spelling.
Select and paste the full invocation into the interpreter; confirm the text survived rather than trusting visual alignment.
A support ticket reveals incompatible assumptions
A user reports that a MATLAB example fails under Octave although the function names appear similar.
Reproduce the call with Octave-specific documentation, review properties and addSwitch behavior, and identify the actual mismatch.
Write down the precise installed version and expected behavior instead of attributing the failure to translation alone.
Deeper teaching notes and release preparation
Translation inventory for GNU Octave
Write a table with four columns: exact argument identifier, input role, accepted form and human description. For named parameters also show the default and the expected value class; for switches show whether absence or presence changes behavior. This table becomes a single source of reference for reviewers who do not edit code.
The right sequence for a first lesson
Begin with one required value. Ask the reader to predict the Results structure, run the function, then add a parameter and a switch. Only after the successful cases should the lesson include one wrong type or unknown name. Translation becomes easier when every sentence refers to a result the reader has just observed.
An audit of parser assumptions
Check the defaults of CaseSensitive, KeepUnmatched, PartialMatching and StructExpand in the targeted release. Do not infer them from another language or from a previous installation. Decide which settings your function explicitly chooses, which remain inherited, and how your documentation will communicate that decision.
The support team’s error corpus
Collect small, private-data-free reproductions for missing required arguments, wrong value types, unknown names, ambiguous prefixes, misplaced positional arguments and unmatched switches. Match each case to a short repair instruction. Review the instructions with both a technical maintainer and a language reviewer so they remain faithful to runtime behavior.
A glossary for world-facing mathematical software
Words such as vector, scalar, default, switch, parameter, validation, unmatched and optional are easy to recognize but easy to mistranslate. Each should have an example showing what the word changes in a call. A stable glossary reduces contradictions across courses and releases while leaving room for natural local phrasing.
Quality gates before publication
Run every printed code sample; verify that default values are correct; check that Unicode text survives all output steps; confirm that errors identify the right category; and test keyboard selection in right-to-left pages. Record the Octave version and the result of each test in a release checklist rather than relying on visual proofreading.
Safety and confidentiality
Parser demonstrations can accidentally teach users to paste private paths or datasets into public support requests. Use disposable vectors and neutral file names. Errors should report useful categories without exposing secrets. When privacy or correctness requirements are unusually important, insist on a separate application review rather than claiming translation alone provides protection.
A useful next step for learners
After reproducing the preview example, design a new function with two required inputs, one named parameter and one switch. Produce a plain-English description of each, then translate the human explanations while holding the function identifiers constant. Write four tests: success, missing required value, bad type and unrecognized name.
Frequently asked questions
Is GNU Octave inputParser the same as MATLAB inputParser?
They serve closely related function-input tasks, but you must check each environment’s documented features and behavior separately. GNU Octave documents addSwitch and several parser properties. Do not assume that a snippet copied from another implementation is portable just because the names look familiar.
Does addSwitch expect a value?
The documented switch form represents an option selected by its presence. It is not the same as a name-value parameter, which pairs a name with a separate value. Test your exact function to see how the chosen switch appears in Results, and do not translate the switch name into a different code token without implementing that alias.
What does PartialMatching do?
It can allow unique prefixes for parameters and switches. The convenience comes with a risk: adding a new similarly named argument can make a once-valid prefix ambiguous. Fully spelled names are usually the clearest choice for printed tutorials and durable scripts.
What happens with KeepUnmatched?
The parser can retain certain unrecognized names and values for later inspection rather than stopping immediately. That is useful for deliberate forwarding, but risky when it hides typos. If you enable it, define how your function will validate or reject those preserved entries before using them.
Can I translate a parameter name into Japanese?
You can translate its explanation in a Japanese guide, but the executable key remains whatever your function declares. To accept Japanese identifiers as aliases, you need explicit implementation and tests; prose translation by itself cannot add alternative syntax to the parser.
Why does an optional argument fail after a parameter?
The documented scheme expects required inputs and then optional positional inputs before the named parameter and switch portion. Reordering a positional argument because it reads better in a sentence may therefore make the call invalid. Follow the parser’s calling order rather than natural-language word order.
What is StructExpand for?
It controls whether a structure can be used as a source of parameter-value entries in supported parsing contexts. A guide should not promise the form without checking the actual setting and implementation. Show a tested example if your audience uses structured configuration.
Can a Locale option change number syntax?
An application-defined locale can choose translated help or display formatting, but it does not automatically modify GNU Octave’s executable grammar. Keep numeric expressions and calculations stable, then handle the human presentation in a separate, tested layer.
Why does Results matter to translation?
Results is the structured outcome of a valid parse, so it tells you what a function actually received. Translators can use it to check whether a phrase describing a default, switch or value corresponds to reality. It should remain program data, not be rewritten as natural-language prose.
How should I translate validation messages?
Explain the violated condition and give a corrected call. Distinguish an unrecognized name from a value with the wrong type. Keep useful technical identifiers for diagnosis; do not replace every runtime failure with one vague translated phrase.
How do I test accents and CJK text?
Use harmless labels or filenames containing accented and non-Latin characters. Verify both the parse result and any downstream file display or export. A correct parser result does not guarantee every later program preserves or renders the text correctly.
What is a good exercise for beginners?
Ask the learner to run one valid function call, inspect Results, omit a named parameter to observe its default and deliberately misuse one switch. The learner then writes a clear explanation in another language without changing runnable identifiers or numerical results.
Sources and next reading
For the described GNU Octave behavior, read the GNU Octave Parsing Arguments manual, which describes addRequired, addOptional, addParameter, addSwitch, Results, UsingDefaults and matching options. For a different implementation with its own documentation and preferred design conventions, see MATLAB inputParser and the neighboring MATLAB translation guide. Verify examples with the actual software versions used in your course or project.
Final perspective
Good multilingual software education does not replace functional syntax with translated captions. It teaches which words carry meaning, which tokens must stay exact and how readers can recover when a call fails. For GNU Octave inputParser, those distinctions become especially clear when a learner examines switches, matching rules, defaults and Results through small runnable examples.