Should canonical-data.json include topics?

[cmccandless]

Something we've run into in the Python track when implementing new exercises is that there is occasionally some confusion about what topics are appropriate for a given exercise. While some exercises may allow for more language-specific topics to be included for that track, most (if not all) exercises could probably have a global list of topics that would be applicable to any track that implements it.

[Insti]

There are 2 questions here:

1. Should we maintain common topics for exercises? I'm not sure that a common store of topics for a problem is a good idea. (I'd be happy to be convinced it is.) Topics tend to be very implementation specific. Are Haskel and NASM (or pick 2 other vastly different languages) going to agree on many?

2. Should we store common topics in canonical-data.json - No canonical-data.json should not include topics, it should only be for common test data. metadata.yml maybe.

[petertseng]

One can imagine some topics that arise from the specification alone, rather than being implementation dependent. If, say, it was determined that primality should be a topic, one might imagine that nth-prime, prime-factors, and sieve would all have that topic.

[ErikSchierboom]

I'm not sure that a common store of topics for a problem is a good idea.

I agree. Although it is tempting, there will probably be lots of cases where the actual topics differ between languages. I'd rather have the languages decide for themselves.

No canonical-data.json should not include topics, it should only be for common test data.

Agreed.

[Insti]

It should be easy to make a tool that queries all track config.jsons and show the topics assigned to each exercise and how many times they are used.

[tleen]

Languages need some flexibility to decide for themselves, especially for language specific features. That being said there are obvious cross track-choices for some exercises so perhaps it could be seeded in the specifications.

[Stargator]

Even when a track implements a specification, they may develop a solution that differs from how users will implement their solution.

So even track maintainers themselves cannot determine what topics a user will consider when developing a solution.

[Smarticles101]

Modified @tleen's exercism-config-visualizations program (my fork here) to get a a list of all exercises, topics that appear in them, and the frequency of the topic. Enjoy :)

Exercise	Topics and frequencies
queen-attack	mathematics: 5, games: 4, logic: 4, classes: 2, optional values: 2, equality: 2, parsing: 2, tuples: 2, arrays: 2, matrices: 2, exception handling: 1, control_flow_loops: 1, text formatting: 1, control_flow_if_statements: 1, structs: 1, booleans: 1, errors: 1, functions: 1, control-flow (conditionals): 1, maybe: 1, control-flow (loops): 1, conditionals: 1, enums: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, optional-values: 1, text-formatting: 1, integers: 1, exception_handling: 1, struct: 1, trait (optional): 1, result: 1, strings: 1
roman-numerals	transforming: 9, strings: 7, mathematics: 5, control_flow_loops: 4, recursion: 3, integers: 3, loops: 3, text_formatting: 2, logic: 2, control-flow (loops): 2, maybe: 1, structs: 1, pattern recognition: 1, memory_management: 1, numbers: 1, metaprogramming: 1, string_manipulation: 1, arrays: 1, string manipulation: 1, conversions: 1, functional: 1, maps: 1, control_flow_conditionals: 1, control-flow (conditionals): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, pattern-recognition: 1, conditionals: 1, mutable: 1, results: 1, struct: 1, traits: 1, sequences: 1, algorithms: 1
word-count	strings: 18, maps: 7, transforming: 7, control_flow_loops: 3, lists: 3, filtering: 2, dictionaries: 2, unicode: 2, parsing: 1, entry api: 1, structs: 1, arrays: 1, reduce: 1, control-flow (loops): 1, memory_management: 1, regular expressions: 1, string_comparison: 1, regular_expressions: 1, conditionals: 1, integers: 1, loops: 1, control_flow_conditionals: 1, control-flow-(loops): 1, regular-expressions: 1, counting: 1, algorithms: 1, logic: 1, pattern_recognition: 1, text_formatting: 1, hashmap: 1, str vs string: 1, chars: 1, sorting: 1
allergies	bitwise_operations: 9, filtering: 8, enumerations: 5, lists: 3, bitwise operations: 2, arrays: 2, integers: 2, control_flow_loops: 2, control_flow_conditionals: 2, control_flow_if_statements: 1, memory_management: 1, enumeration: 1, booleans: 1, conditionals: 1, control-flow (conditionals): 1, control-flow (loops): 1, loops: 1, structs: 1, text_formatting: 1, bitwise-operations: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, control_flow_if_else_statements: 1, classes: 1, mathematics: 1, struct: 1, enum: 1, bitwise (probably): 1, vectors: 1, filter: 1
robot-simulator	strings: 5, classes: 4, tuples: 4, enumerations: 3, loops: 3, structs: 2, games: 2, parsing: 2, records: 2, concurrency: 1, control_flow_if_statements: 1, variable_argument_lists: 1, control-flow (conditionals): 1, control-flow (loops): 1, pointers: 1, exception handling: 1, sequences: 1, define type: 1, logic: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, exception_handling: 1, oop: 1, algorithms: 1, conditionals: 1, variables: 1, immutability: 1, enum: 1
crypto-square	transforming: 11, strings: 11, algorithms: 6, text_formatting: 5, arrays: 4, lists: 2, security: 2, filtering: 2, cryptography: 2, control_flow_loops: 2, sorting: 2, control-flow-(loops): 1, text formatting: 1, control-flow (loops): 1, control-flow (conditionals): 1, mathematics: 1, classes: 1, control_flow_conditionals: 1, string manipulation: 1, control-flow-(conditionals): 1, regular expressions: 1, regular-expressions: 1, text-formatting: 1, looping: 1, str vs string: 1, primitive types: 1, iterators: 1, chars: 1, ascii: 1
triangle	mathematics: 13, integers: 8, booleans: 3, discriminated_unions: 3, classes: 3, enumerations: 2, control_flow_if_else_statements: 2, control_flow_conditionals: 2, conditionals: 2, exception_handling: 2, exception handling: 1, control-flow (if-statements): 1, control-flow (loops): 1, control-flow (conditionals): 1, input_validation: 1, number_comparison: 1, boolean_logic: 1, logic: 1, number theory: 1, structs: 1, language basics: 1, filtering: 1, floating_point_numbers: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, pattern_matching: 1, object_oriented_programming: 1, struct: 1
atbash-cipher	strings: 13, algorithms: 9, transforming: 9, cryptography: 3, control_flow_loops: 3, arrays: 2, security: 2, control-flow (conditionals): 1, control-flow (loops): 1, control_flow_if_else_statements: 1, regular expressions: 1, text formatting: 1, ascii: 1, control_flow_conditionals: 1, pattern_matching: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, regular-expressions: 1, text-formatting: 1, text_formatting: 1, maps: 1, conditionals: 1, loops: 1, str vs string: 1, primitive types: 1, iterators: 1, chars: 1, sequences: 1
nucleotide-count	strings: 12, maps: 8, parsing: 4, control_flow_loops: 3, dictionaries: 2, exception_handling: 2, control_flow_loops_switch_if_statements: 1, memory_management: 1, classes: 1, associative arrays: 1, enumerables: 1, match: 1, string_processing: 1, string_comparison: 1, conditionals: 1, text_formatting: 1, integers: 1, searching: 1, sorting: 1, counting: 1, lists: 1, transforming: 1, result: 1, filter: 1, entry api: 1, mutablity: 1, either: 1
largest-series-product	strings: 11, integers: 11, transforming: 7, mathematics: 4, loops: 2, control_flow_loops: 2, control-flow-(loops): 1, control-flow (loops): 1, exception handling: 1, regular expressions: 1, algorithms: 1, sequences: 1, maybe: 1, performance_optimizations: 1, type_conversion: 1, control-flow-(conditionals): 1, control-flow (conditionals): 1, exception-handling: 1, regular-expressions: 1, exception_handling: 1, logic: 1, conditionals: 1, result: 1, windows: 1, higher-order functions: 1, char: 1, optional values: 1
wordy	parsing: 10, strings: 9, transforming: 7, mathematics: 2, regular_expressions: 2, pattern_matching: 2, logic: 2, type_conversion: 2, integers: 2, control-flow-(loops): 1, conditionals: 1, maybe: 1, exception_handling: 1, exception handling: 1, regular expressions: 1, control-flow (loops): 1, control-flow-(conditionals): 1, pattern recognition: 1, exception-handling: 1, pattern-recognition: 1, regular-expressions: 1, control-flow (conditionals): 1, result: 1, string parsing: 1, operators (optional): 1, optional values: 1
pythagorean-triplet	mathematics: 10, integers: 6, algorithms: 4, records: 2, lists: 2, logic: 2, tuples: 2, number theory: 1, integer: 1, control-flow (conditionals): 1, control-flow (loops): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, sequences: 1, control_flow_loops: 1, conditionals: 1, equality: 1, loops: 1, variables: 1, enumerations: 1, sets: 1, overloading: 1, filtering: 1, searching: 1, option: 1, control_flow_if_else_statements: 1
meetup	dates: 12, time: 4, control_flow_if_statements: 2, strings: 2, equality: 2, conditionals: 2, interfaces: 1, pattern_recognition: 1, control-flow (conditionals): 1, control-flow (loops): 1, exception handling: 1, structs: 1, time_functions: 1, preprocessor_x_macros_in_test: 1, type_conversion: 1, functions: 1, enumerations: 1, loops: 1, control_flow_conditionals: 1, filtering: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, control_flow_loops: 1, parsing: 1, transforming: 1
pangram	strings: 17, searching: 4, algorithms: 3, control_flow_loops: 3, lists: 2, maps: 2, control_flow_if_else_statements: 2, loops: 2, regular_expressions: 2, control-flow (loops): 1, string_transformation: 1, language basics: 1, string manipulation: 1, control-flow: 1, enumerations: 1, pattern_matching: 1, control-flow (conditionals): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, transforming: 1, conditionals: 1, filtering: 1, logic: 1, filter: 1, ascii (optional): 1
series	strings: 11, arrays: 6, transforming: 4, lists: 3, conditionals: 2, loops: 2, text_formatting: 1, string manipulation: 1, string_processing: 1, control-flow (loops): 1, exception handling: 1, text formatting: 1, memory_management: 1, refactoring: 1, control_flow_if_statements: 1, logic: 1, type_conversion: 1, control-flow-(loops): 1, exception-handling: 1, text-formatting: 1, control_flow_loops: 1, coroutines: 1, algorithms: 1, vectors: 1, sequences: 1
hamming	strings: 17, filtering: 9, control_flow_loops: 5, equality: 4, loops: 3, error handling: 1, control-flow (foreach): 1, control-flow (loops): 1, control-flow (conditionals): 1, optional values: 1, arrays: 1, maybe: 1, string_comparison: 1, control_flow_conditionals: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, iterating_over_two_lists_at_once: 1, conditionals: 1, sequences: 1, sets: 1, algorithms: 1, logic: 1, result: 1, integers: 1
ocr-numbers	parsing: 9, strings: 5, pattern_recognition: 5, lists: 3, equality: 2, integers: 2, transforming: 2, enumerations: 1, pattern recognition: 1, text formatting: 1, exception_handling: 1, control-flow (conditionals): 1, control-flow (loops): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, text-formatting: 1, control_flow_loops: 1, algorithms: 1, exception handling: 1, lines: 1, chunks: 1, slices: 1, loops: 1
secret-handshake	bitwise_operations: 8, arrays: 5, lists: 5, integers: 3, bitwise operations: 2, algorithms: 2, conditionals: 2, games: 2, loops: 2, mathematics: 2, transforming: 2, cryptography: 1, control-flow (conditionals): 1, control-flow (loops): 1, strings: 1, binary_representation: 1, bitwise-operations: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, control_flow_if_else_statements: 1, logic: 1, bitwise__operations: 1, control_flow_conditionals: 1, enumerations: 1
custom-set	sets: 9, equality: 4, lists: 3, arrays: 2, recursion: 2, generics: 2, data structures: 1, struct: 1, filtering: 1, loops: 1, define type: 1, control-flow (conditionals): 1, control-flow (loops): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, data-structures: 1, classes: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, functional_programming: 1, generic over type: 1, vector: 1, library reimplementation: 1
kindergarten-garden	enumerations: 5, strings: 5, arrays: 4, parsing: 4, lists: 2, control-flow (conditionals): 1, text formatting: 1, records: 1, searching: 1, structs: 1, control-flow (loops): 1, transforming: 1, loops: 1, pattern_recognition: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, text-formatting: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, classes: 1, optional_values: 1, variables: 1, logic: 1
clock	time: 11, classes: 4, structural_equality: 4, text_formatting: 3, logic: 3, integers: 2, strings: 2, structural equality: 2, dates: 2, globalization: 2, equality: 2, mathematics: 2, transforming: 1, protocols: 1, structs: 1, preprocessor_x_macros_in_test: 1, define type: 1, instance num: 1, object_oriented_programming: 1, control_flow_if_statements: 1, traits: 1, derive: 1, struct: 1
sieve	mathematics: 14, filtering: 8, integers: 5, control_flow_loops: 3, algorithms: 3, loops: 3, lists: 3, recursion: 2, sorting: 1, control-flow (loops): 1, control_flow_if_statements: 1, memory_management: 1, number theory: 1, control-flow (conditionals): 1, control_flow_conditionals: 1, maps: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, control_flow_if_else_statements: 1, conditionals: 1, vector: 1, map: 1, while let (optional): 1
all-your-base	integers: 10, transforming: 7, mathematics: 7, arrays: 3, control_flow_loops: 2, parsing: 2, control-flow (loops): 1, exception handling: 1, optional values: 1, control-flow (conditionals): 1, maybe: 1, control_flow_if_else_statements: 1, exception_handling: 1, loops: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, result: 1, enumerate: 1, fold: 1, map: 1, lists: 1, conditionals: 1
run-length-encoding	algorithms: 9, strings: 8, transforming: 8, parsing: 3, text_formatting: 3, text formatting: 1, regular expressions: 1, pattern recognition: 1, control-flow (conditionals): 1, integers: 1, pattern_matching: 1, exception handling: 1, exception-handling: 1, pattern-recognition: 1, regular-expressions: 1, text-formatting: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, loop: 1, string concatenation: 1, conversion between string and int: 1, use of primitive char: 1, control-flow-(conditionals): 1
say	strings: 9, text_formatting: 7, transforming: 7, loops: 3, parsing: 3, mathematics: 2, integers: 2, text formatting: 2, numbers: 1, exception handling: 1, control-flow (conditionals): 1, control-flow (loops): 1, maybe: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, text-formatting: 1, control_flow_loops: 1, logic: 1, pattern_matching: 1, string concatenation: 1, modulus: 1, optional values: 1
pascals-triangle	mathematics: 14, lists: 4, recursion: 4, arrays: 3, control_flow_loops: 3, algorithms: 2, control-flow (loops): 2, strings: 2, integers: 2, control-flow (conditionals): 1, control_flow_if_else_statements: 1, memory_management: 1, number theory: 1, exception_handling: 1, text formatting: 1, matrices: 1, sequences: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, text-formatting: 1, control_flow_conditionals: 1, vec: 1, index (optional): 1
bob	strings: 17, control_flow_if_else_statements: 6, control_flow_conditionals: 4, conditionals: 3, parsing: 2, polymorfism: 2, unicode: 2, control-flow (if-else statements): 2, control-flow (conditionals): 1, pattern matching: 1, string manipulation: 1, control-flow (if-statements): 1, regular expressions: 1, control_flow: 1, booleans: 1, control-flow-(conditionals): 1, pattern-recognition: 1, regular-expressions: 1, string_processing: 1, equality: 1, chars: 1, string functions: 1, pattern recognition: 1
robot-name	randomness: 17, strings: 11, classes: 3, text_formatting: 3, regular_expressions: 2, pattern_matching: 2, sets: 2, control-flow-(conditionals): 1, regular expressions: 1, io monad: 1, random: 1, exception handling: 1, control-flow (conditionals): 1, random numbers: 1, variables: 1, define type: 1, exception-handling: 1, regular-expressions: 1, mutable_state: 1, struct: 1, slices: 1, lifetimes: 1, self mut: 1
matrix	matrices: 9, arrays: 5, parsing: 4, strings: 3, type_conversion: 3, integers: 2, loops: 2, control-flow (conditionals): 1, text formatting: 1, exception_handling: 1, structs: 1, string_processing: 1, define type: 1, data structures: 1, control-flow (loops): 1, pattern_matching: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, data-structures: 1, text-formatting: 1, control_flow_loops: 1, vectors: 1
binary-search	searching: 11, arrays: 9, algorithms: 7, recursion: 4, lists: 4, control_flow_loops: 2, control_flow_if_else_statements: 2, control-flow (conditionals): 1, control-flow (loops): 1, sorting: 1, collections: 1, optional values: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, integers: 1, search: 1, conditionals: 1, loops: 1, slices: 1, trait (optional): 1, option: 1, generics: 1
simple-cipher	strings: 9, algorithms: 7, transforming: 7, mathematics: 3, randomness: 3, cryptography: 3, control-flow (loops): 1, optional values: 1, encryption: 1, text formatting: 1, string_processing: 1, control-flow (conditionals): 1, io monad: 1, random: 1, mutable state: 1, exception_handling: 1, security: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, text-formatting: 1, text_formatting: 1, interfaces: 1
protein-translation	strings: 10, transforming: 3, algorithms: 3, control-flow-(conditionals): 3, control-flow-(loops): 3, lists: 2, sequences: 2, pattern_matching: 2, control_flow_if_else_statements: 1, string_processing: 1, maps: 1, pattern matching: 1, arrays: 1, conditionals: 1, loops: 1, filtering: 1, control_flow_loops: 1, exception_handling: 1, struct: 1, hash map: 1, lifetimes: 1, result: 1
beer-song	strings: 13, text_formatting: 7, algorithms: 4, conditionals: 4, loops: 3, control_flow_loops: 3, control_flow_conditionals: 2, control_flow_if_else_statements: 2, text formatting: 2, looping: 2, control-flow (conditionals): 1, variables: 1, integers: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, control-flow (loops): 1, refactoring: 1, case: 1, string concatenation: 1, vector (optional): 1, loop: 1, control-flow: 1
phone-number	parsing: 11, strings: 10, transforming: 10, regular_expressions: 4, conditionals: 3, text_formatting: 2, control_flow_if_else_statements: 2, pattern_matching: 2, control_flow_conditionals: 1, control_flow_loops: 1, string_comparison: 1, string_manipulation: 1, maybe: 1, memory_management: 1, interfaces: 1, option: 1, format: 1, unwrap_or: 1, iters: 1, match: 1, optional values: 1
space-age	floating_point_numbers: 9, mathematics: 6, classes: 3, discriminated_unions: 3, functions: 2, floating-point numbers: 2, conditionals: 2, if_else_statements: 1, pattern_matching: 1, interfaces: 1, domain-specific languages: 1, floating-point-numbers: 1, arithmetic: 1, floats: 1, integers: 1, custom trait: 1, from trait: 1, default trait implementation: 1, dates: 1, enumerations: 1, transforming: 1
binary-search-tree	trees: 9, searching: 8, algorithms: 5, recursion: 5, sorting: 2, generics: 2, define type: 1, optional_values: 1, control-flow (conditionals): 1, structs: 1, control-flow (loops): 1, maybe: 1, overloading: 1, graphs: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, coroutines: 1, exception_handling: 1, classes: 1, object_oriented_programming: 1, lists: 1
linked-list	lists: 9, algorithms: 5, generics: 3, classes: 2, arrays: 2, optional values: 2, control-flow (conditionals): 1, control-flow (loops): 1, conditionals: 1, define type: 1, data structures: 1, library reimplementation: 1, maybe: 1, mutable state: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, data-structures: 1, optional-values: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, io monad: 1
saddle-points	matrices: 9, lists: 5, mathematics: 4, integers: 4, sets: 3, arrays: 3, conditionals: 2, parsing: 2, equality: 2, loops: 2, tuples: 2, control-flow (conditionals): 1, searching: 1, exception handling: 1, optional values: 1, control-flow (loops): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, optional-values: 1, algorithms: 1
palindrome-products	algorithms: 7, strings: 5, mathematics: 5, tuples: 4, integers: 3, loops: 2, control-flow (conditionals): 1, control-flow (loops): 1, exception handling: 1, functions: 1, pointers: 1, conditionals: 1, lists: 1, structs: 1, maps: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, arithmetic: 1, optional values: 1, sets: 1
circular-buffer	queues: 5, classes: 4, exception_handling: 3, data-structures: 2, lists: 2, arrays: 2, data structures: 1, class templates: 1, generics: 1, exception handling: 1, control-flow (conditionals): 1, structs: 1, control-flow (loops): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, control_flow_if_else_statements: 1, algorithms: 1, conditionals: 1, buffer reimplementation: 1, records: 1
grade-school	sorting: 11, maps: 8, lists: 5, arrays: 4, conditionals: 2, strings: 2, define type: 1, sequences: 1, structs: 1, interfaces: 1, parsing: 1, classes: 1, control_flow_if_else_statements: 1, transforming: 1, integers: 1, filtering: 1, struct: 1, entry api: 1, vec: 1, option: 1, variables: 1
perfect-numbers	integers: 10, mathematics: 9, discriminated_unions: 3, control_flow_if_else_statements: 2, arrays: 2, algorithms: 2, filtering: 2, enumerations: 2, discriminated unions: 1, maybe: 1, control-flow (conditionals): 1, control-flow (loops): 1, exception_handling: 1, number_theory: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, control_flow_loops: 1, loops: 1, logic: 1, control_flow_conditionals: 1, number theory: 1
luhn	strings: 11, algorithms: 9, transforming: 6, mathematics: 4, integers: 3, loops: 2, control-flow (conditionals): 1, booleans: 1, control-flow (loops): 1, type_conversion: 1, higher-order functions: 1, control-flow-(loops): 1, control_flow_if_else_statements: 1, control_flow_loops: 1, arithmetic: 1, conditionals: 1, pattern_matching: 1, security: 1, str to digits: 1, iterators: 1, control-flow-(conditionals): 1
bowling	algorithms: 8, arrays: 3, games: 3, control-flow-(conditionals): 2, control-flow-(loops): 2, exception-handling: 2, parsing: 2, text-formatting: 2, conditionals: 2, exception_handling: 2, control_flow_loops: 1, lists: 1, integers: 1, mathematics: 1, control_flow_if_else_statements: 1, control-flow (loops): 1, struct: 1, result: 1, goofy bowling logic: 1, control-flow (if-else statements): 1, either: 1
anagram	strings: 17, filtering: 13, control_flow_loops: 2, arrays: 2, parsing: 2, equality: 2, loops: 2, algorithms: 2, conditionals: 1, sequences: 1, string_transformation: 1, structs: 1, sorting: 1, control_flow_if_else_statements: 1, logic: 1, lifetimes: 1, str vs string: 1, iter: 1, vector: 1, lists: 1
rna-transcription	strings: 15, transforming: 14, maps: 3, control_flow_loops: 3, loops: 3, conditionals: 2, maybe: 1, control-flow (foreach): 1, associative_arrays: 1, string_manipulation: 1, control_flow_case_statements: 1, string manipulation: 1, control_flow_conditionals: 1, error handling: 1, logic: 1, result: 1, match: 1, struct: 1, str vs string: 1, optional values: 1
bracket-push	strings: 12, parsing: 9, stacks: 5, control-flow-(loops): 1, control-flow (conditionals): 1, control-flow (loops): 1, exception handling: 1, stack: 1, control-flow-(conditionals): 1, pattern_matching: 1, exception-handling: 1, algorithms: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, conditionals: 1, looping: 1, recursion: 1, from trait: 1, stack or recursion: 1
sum-of-multiples	mathematics: 6, lists: 6, transforming: 4, integers: 4, loops: 2, arrays: 2, control_flow_loops: 2, control_flow_case_statements: 1, control-flow (conditionals): 1, control-flow (loops): 1, number theory: 1, conditionals: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, control_flow_if_else_statements: 1, algorithm: 1, borrowing: 1, filtering: 1, sets: 1
nth-prime	mathematics: 12, algorithms: 5, integers: 5, loops: 3, control_flow_if_else_statements: 2, control_flow_loops: 2, exception_handling: 2, lists: 2, optional values: 1, control-flow (conditionals): 1, number theory: 1, arrays: 1, control-flow (loops): 1, exception handling: 1, performance_optimizations: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, maybe: 1
pig-latin	strings: 12, transforming: 9, text_formatting: 3, games: 2, conditionals: 2, lists: 2, regular_expressions: 1, regular expressions: 1, pattern_matching: 1, string_processing: 1, control-flow (conditionals): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, regular-expressions: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, control-flow (loops): 1, loops: 1, arrays: 1
change	algorithms: 7, integers: 5, arrays: 4, mathematics: 4, searching: 3, performance: 2, loops: 2, lists: 2, maybe: 1, recursion: 1, optional values: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, dynamic_programming: 1, control-flow (conditionals): 1, control-flow (loops): 1, logic: 1, exception_handling: 1
scrabble-score	strings: 13, transforming: 7, maps: 6, loops: 3, games: 3, control-flow (loops): 2, control_flow_loops: 2, mathematics: 1, structs: 1, searching: 1, control-flow (conditionals): 1, pattern_matching: 1, pointers: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, integers: 1, chaining higher-order functions: 1, hashmap (optional): 1
tournament	parsing: 7, text_formatting: 6, sorting: 4, strings: 3, maps: 2, loops: 2, control_flow_loops: 1, integers: 1, transforming: 1, string_processing: 1, formatting: 1, arrays: 1, records: 1, text_parsing: 1, conditionals: 1, enum: 1, hashmap: 1, structs: 1
collatz-conjecture	mathematics: 13, integers: 9, recursion: 7, algorithms: 5, control-flow (loops): 5, control-flow (conditionals): 4, control_flow_conditionals: 3, control_flow_loops: 3, exception_handling: 2, conditionals: 2, functions: 1, maybe: 1, number theory: 1, integer: 1, recursivity: 1, control_flow_if_else_statements: 1, loops: 1, error handling with result<t, e>: 1
prime-factors	mathematics: 15, integers: 10, algorithms: 6, control_flow_loops: 3, lists: 2, loops: 2, filtering: 1, number theory: 1, conditionals: 1, control-flow (loops): 1, control-flow (conditionals): 1, control_flow_conditionals: 1, arrays: 1, maps: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, control_flow_if_else_statements: 1, logic: 1
rectangles	strings: 3, algorithms: 2, transforming: 2, pattern_recognition: 2, arrays: 2, logic: 2, parsing: 2, performance: 1, matrices: 1, control-flow (conditionals): 1, control_flow_if_else_statements: 1, control_flow_loops: 1, control-flow (loops): 1, search: 1, enum: 1, structs: 1, traits: 1, algorithm: 1
diamond	strings: 7, text_formatting: 5, algorithms: 4, arrays: 3, loops: 3, lists: 3, parsing: 2, games: 2, conditionals: 1, control-flow (conditionals): 1, control-flow (loops): 1, exception handling: 1, text formatting: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, text-formatting: 1, control_flow_loops: 1
react	reactive_programming: 5, events: 4, functions: 2, classes: 2, reactive programming: 2, generics: 2, closures: 1, nested classes: 1, higher-order functions: 1, memory_management: 1, algorithms: 1, callbacks: 1, interfaces: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, graphs: 1, lifetimes: 1, delegates: 1
twelve-days	strings: 6, algorithms: 4, text_formatting: 4, regular expressions: 2, pattern recognition: 2, control-flow (conditionals): 2, control-flow (loops): 2, sequences: 1, polymorfism: 1, reduce: 1, enumerations: 1, pattern_recognition: 1, string_formatting: 1, arrays: 1, conditionals: 1, loops: 1, polymorphism: 1, lists: 1
raindrops	strings: 10, filtering: 8, text_formatting: 4, integers: 4, transforming: 3, mathematics: 2, conditionals: 2, control_flow_conditionals: 2, control_flow_if_else_statements: 2, input_validation: 1, control-flow (conditionals): 1, control-flow (if-statements): 1, language basics: 1, control-flow-(conditionals): 1, text formatting: 1, case (or format): 1, mutable string: 1, logic: 1
alphametics	algorithms: 3, parsing: 3, games: 2, maps: 2, strings: 2, mathematics: 2, performance: 1, control_flow_loops: 1, dictionaries: 1, maybe: 1, control_flow_if_else_statements: 1, logic: 1, conditionals: 1, string parsing: 1, combinations: 1, external crates (optional): 1, optional values: 1
difference-of-squares	integers: 11, mathematics: 11, control_flow_loops: 5, algorithms: 4, control_flow_conditionals: 1, control-flow (foreach): 1, template metaprogramming: 1, functional: 1, string_comparison: 1, control-flow (loops): 1, string_transformation: 1, number theory: 1, loops: 1, floating_point_numbers: 1, control-flow-(loops): 1, fold: 1, map: 1
strain	filtering: 8, sequences: 5, arrays: 3, callbacks: 2, lists: 2, algorithms: 2, library reimplementation: 1, control-flow (loops): 1, collections: 1, loops: 1, lazy evaluation: 1, control-flow (conditionals): 1, control_flow_conditionals: 1, control_flow_loops: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, generics: 1
list-ops	lists: 6, recursion: 4, filtering: 3, functional_programming: 3, loops: 2, library reimplementation: 1, callbacks: 1, control-flow (loops): 1, data structures: 1, accumulator-strictness: 1, data-structures: 1, arrays: 1, control_flow_loops: 1, variables: 1, searching: 1, conditionals: 1, generics: 1
word-search	searching: 5, strings: 4, tuples: 2, matrices: 2, optional values: 1, equality: 1, text formatting: 1, parsing: 1, control_flow_loops: 1, optional_values: 1, control-flow (conditionals): 1, control-flow (loops): 1, games: 1, logic: 1, pattern_matching: 1, control_flow_if_else_statements: 1, arrays: 1
rotational-cipher	strings: 9, transforming: 4, logic: 2, algorithms: 2, control-flow (conditionals): 2, cryptography: 2, integers: 2, text formatting: 1, string_processing: 1, loops: 1, control-flow (loops): 1, str vs string: 1, primitive types: 1, iterators: 1, chars: 1, ascii: 1
acronym	strings: 15, transforming: 10, control_flow_loops: 2, regular_expressions: 2, loops: 2, regular expressions: 1, vec: 1, control-flow (loops): 1, memory_management: 1, searching: 1, control-flow-(loops): 1, regular-expressions: 1, map: 1, flat_map: 1, filter: 1, parsing: 1
grains	integers: 10, mathematics: 9, bitwise_operations: 4, type_conversion: 2, control_flow_loops: 2, performance_optimizations: 1, if_else_statements: 1, optional values: 1, control-flow (loops): 1, number theory: 1, variables: 1, control-flow-(loops): 1, floating-point numbers: 1, algorithms: 1, panic: 1, maybe: 1
binary	strings: 4, mathematics: 3, integers: 3, control_flow_loops: 2, bitwise_operations: 2, exception handling: 1, control_flow_if_statements: 1, regular expressions: 1, control-flow (conditionals): 1, control-flow (loops): 1, control_flow_conditionals: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, regular-expressions: 1, control_flow_if_else_statements: 1
etl	transforming: 14, maps: 11, lists: 4, control_flow_loops: 3, dictionaries: 2, integers: 2, loops: 2, associative arrays: 1, arrays: 1, control-flow (loops): 1, string manipulation: 1, control-flow (foreach): 1, control-flow-(loops): 1, btree: 1, sequences: 1, strings: 1
sublist	lists: 10, arrays: 5, searching: 3, control_flow_loops: 2, generics: 2, loops: 2, looping: 2, enumeration: 1, pointers: 1, control_flow_if_statements: 1, recursion: 1, control_flow_if_else_statements: 1, control-flow (loops): 1, enum: 1, generic over type: 1, enumerations: 1
poker	parsing: 6, games: 5, sorting: 5, discriminated_unions: 2, equality: 1, pattern_matching: 1, sequences: 1, strings: 1, traits: 1, conditionals: 1, loops: 1, lifetimes: 1, struct: 1, string parsing: 1, enum: 1, lists: 1
hello-world	strings: 11, optional_values: 6, text_formatting: 6, optional values: 2, control_flow_if_statements: 2, text formatting: 2, control-flow (conditionals): 1, stdout: 1, language basics: 1, control-flow-(conditionals): 1, optional-values: 1, text-formatting: 1, setting_up_ocaml_dev_environment: 1, conditionals: 1, println!: 1
minesweeper	transforming: 8, parsing: 6, games: 5, arrays: 5, lists: 3, strings: 3, algorithms: 2, loops: 2, matrices: 2, board state: 1, integers: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, exception_handling: 1, conditionals: 1
connect	parsing: 5, games: 4, arrays: 3, transforming: 3, graphs: 2, control-flow (loops): 2, maps: 2, control-flow (conditionals): 2, searching: 2, loops: 1, maybe: 1, search: 1, recursion: 1, optional values: 1, algorithms: 1
two-bucket	algorithms: 3, logic: 2, arrays: 2, parsing: 2, games: 2, loops: 2, control-flow (loops): 1, control-flow (conditionals): 1, control-flow-(conditionals): 1, control-flow-(loops): 1, exception-handling: 1, mathematics: 1, conditionals: 1, algorithm: 1, exception handling: 1
simple-linked-list	lists: 9, algorithms: 2, generics: 2, arrays: 2, classes: 2, define type: 1, library reimplementation: 1, data structures: 1, exception_handling: 1, recursion: 1, data-structures: 1, conditionals: 1, type_conversion: 1, struct: 1, transforming: 1
isbn-verifier	strings: 7, loops: 5, conditionals: 3, pattern_matching: 3, control_flow_loops: 2, mathematics: 2, loop: 1, string_processing: 1, regular_expressions: 1, arrays: 1, integers: 1, control_flow_conditionals: 1, logic: 1, conversion between string and int: 1, pattern_recognition: 1
accumulate	transforming: 5, lists: 4, recursion: 3, algorithms: 2, sequences: 2, callbacks: 2, extension_methods: 1, reduce: 1, control-flow (loops): 1, lazy evaluation: 1, library reimplementation: 1, control-flow-(loops): 1, extension methods: 1, function pointer: 1, generics: 1
variable-length-quantity	algorithms: 5, bitwise_operations: 5, bitwise operations: 2, transforming: 2, arrays: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, integers: 1, encodings: 1, slices: 1, bitwise: 1, result: 1, discriminated unions: 1, lists: 1
dominoes	tuples: 5, lists: 4, algorithms: 2, enumerations: 1, recursion: 1, sorting: 1, trees: 1, arrays: 1, maybe: 1, search: 1, graph theory: 1, searching: 1, optional values: 1, games: 1
food-chain	algorithms: 7, strings: 5, text_formatting: 3, loops: 2, text formatting: 2, control_flow_loops: 2, conditionals: 2, pattern_recognition: 1, recursion: 1, refactoring: 1, arrays: 1, lists: 1, text-formatting: 1, control_flow_if_else_statements: 1
house	strings: 7, text_formatting: 6, algorithms: 4, recursion: 3, arrays: 2, control-flow (loops): 1, control-flow (conditionals): 1, refactoring: 1, conditionals: 1, loops: 1, control_flow_loops: 1, pattern_recognition: 1, text formatting: 1
forth	parsing: 6, stacks: 5, strings: 2, define type: 1, either: 1, stack: 1, mathematics: 1, lists: 1, logic: 1, domain_specific_languages: 1, interpreters: 1, parser reimplementation: 1, exception_handling: 1
proverb	strings: 3, algorithms: 2, arrays: 2, control-flow (loops): 1, format: 1, text formatting: 1, control-flow (conditionals): 1, text_formatting: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, optional-values: 1, text-formatting: 1, optional values: 1
spiral-matrix	matrices: 6, arrays: 3, algorithms: 2, loops: 2, control-flow (loops): 1, control-flow (conditionals): 1, recursivity: 1, data structures: 1, lists: 1, transforming: 1, integers: 1, mathematics: 1
isogram	strings: 16, filtering: 9, conditionals: 2, control_flow_loops: 2, control_flow_if_else_statements: 2, loops: 2, arrays: 1, sequences: 1, parsing: 1, algorithms: 1, chars: 1, iterators: 1
two-fer	strings: 8, optional_values: 4, text_formatting: 3, conditionals: 3, optional values: 1, logic: 1, control_flow_conditionals: 1, text formatting: 1, booleans: 1, control_flow_if_else_statements: 1, control-flow-(conditionals): 1, control-flow (conditionals): 1
octal	strings: 3, mathematics: 2, integers: 2, control-flow-(conditionals): 1, control-flow (conditionals): 1, regular expressions: 1, control-flow (loops): 1, control-flow-(loops): 1, regular-expressions: 1, bitwise_operations: 1, control_flow_if_else_statements: 1, control_flow_loops: 1
leap	integers: 12, logic: 9, booleans: 7, control_flow_if_else_statements: 4, control_flow_conditionals: 3, conditionals: 3, mathematics: 2, boolean_logic: 1, input_validation: 1, logical_operators: 1, equality: 1, language basics: 1
pov	graphs: 5, recursion: 4, searching: 3, trees: 2, transforming: 1, structs: 1, maybe: 1, algorithms: 1, control_flow_if_else_statements: 1, control_flow_loops: 1, exception_handling: 1
gigasecond	dates: 12, time: 9, integers: 2, function overloading: 1, language basics: 1, interfaces: 1, transforming: 1, variables: 1, crates: 1, mathematics: 1, date: 1
bank-account	concurrency: 4, classes: 2, integers: 2, parallellism: 1, define type: 1, optional_values: 1, maybe: 1, mutable state: 1, exception_handling: 1, control_flow_if_else_statements: 1, io monad: 1
flatten-array	recursion: 8, lists: 6, arrays: 6, algorithms: 2, looping: 2, searching: 2, control_flow_loops: 1, pattern matching: 1, loops: 1, transforming: 1, control_flow_if_else_statements: 1
trinary	mathematics: 4, strings: 3, integers: 3, control-flow (conditionals): 1, control-flow (loops): 1, regular expressions: 1, control_flow_conditionals: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, regular-expressions: 1
transpose	strings: 12, transforming: 7, loops: 5, arrays: 4, lists: 4, matrices: 4, text_formatting: 4, algorithms: 2, control_flow_loops: 1
book-store	recursion: 4, algorithms: 4, lists: 3, integers: 2, mathematics: 2, floating_point_numbers: 2, loops: 1, groups: 1, set theory: 1
hexadecimal	mathematics: 3, strings: 3, integers: 2, control-flow (conditionals): 1, control-flow (loops): 1, regular expressions: 1, control-flow-(conditionals): 1, control-flow-(loops): 1, regular-expressions: 1
diffie-hellman	algorithms: 6, integers: 3, transforming: 3, mathematics: 2, control-flow (conditionals): 2, control-flow (loops): 2, arrays: 2, exception handling: 2, cryptography: 1
zipper	trees: 5, recursion: 4, searching: 4, define type: 1, maybe: 1, functional_programming: 1, generics: 1, optional values: 1
dot-dsl	domain_specific_languages: 3, classes: 2, equality: 2, lists: 1, graphs: 1, object_oriented_programming: 1, test_driven_development: 1, transforming: 1
parallel-letter-frequency	parallellism: 3, transforming: 3, dictionaries: 2, concurrency: 1, multi-threading: 1, maps: 1, sequences: 1, strings: 1
ledger	refactoring: 3, globalization: 2, strings: 2, text_formatting: 2, dates: 1, integers: 1, records: 1, sorting: 1
rail-fence-cipher	algorithms: 5, strings: 4, transforming: 3, text_formatting: 3, cryptography: 2, lists: 2, control_flow_if_else_statements: 1, control_flow_loops: 1
markdown	refactoring: 5, parsing: 2, transforming: 2, strings: 1, conditionals: 1, pattern_matching: 1
scale-generator	algorithms: 2, parsing: 2, enumerations: 1, string_processing: 1, strings: 1, pattern_matching: 1
complex-numbers	mathematics: 5, tuples: 2, define type: 1, number theory: 1, classes: 1, floating_point_numbers: 1
error-handling	exception_handling: 4, error_handling: 1, input_validation: 1, discriminated_unions: 1, optional_values: 1
grep	files: 3, searching: 3, strings: 2, text_formatting: 2, enumerations: 1
go-counting	optional_values: 3, parsing: 3, tuples: 3, maybe: 1, classes: 1
tree-building	refactoring: 4, trees: 4, records: 2, sorting: 2, maps: 1
decimal	struct: 1, traits: 1, string parsing: 1, bigint: 1, external crates (optional): 1
zebra-puzzle	logic: 4, arrays: 1, algorithms: 1, searching: 1
reverse-string	strings: 3, string: 1, &str: 1, iterator: 1
luhn-from	from trait: 1, str to digits: 1, iterators: 1, higher-order functions: 1
luhn-trait	custom trait: 1, str to digits: 1, iterators: 1, higher-order functions: 1
sgf-parsing	parsing: 3, transforming: 3, maybe: 1
paasio	concurrency: 1, interfaces: 1, networking: 1
macros	macros: 1, macros-by-example: 1, hashmap: 1
hangman	reactive_programming: 3, events: 1
lens-person	lenses: 1

[ErikSchierboom]

We no longer support topics in Exercism v3, which have been replaced with concepts (listed in the practices and prerequisites fields). The same problems mentioned in this issue apply: concepts will vary between tracks greatly, and the same concepts might have different names in different tracks. I don't think there is currently a good way for us to list these topics, so I'll close this issue. If someone feels this issue should remain open, feel free to re-open.