Master programming syntax, solve interactive challenges & run live code in Syntaxis Explore Arena →
menu_book Course Curriculum (Erlang) expand_more
Syntax and Terms
Module declarations Export attributes Atoms Numbers Tuples Lists Maps Binaries Variables and single assignment Pattern matching
Functions and Guards
Function clauses Arity Guards Case expressions If expressions Anonymous funs Higher-order functions List recursion Tail recursion List comprehensions
Lists Maps and Binaries
lists map lists filter lists foldl maps get maps update maps fold Binary construction Binary pattern matching Bit syntax sizes String unicode binaries
Processes
spawn Self pid Send operator Receive Receive timeout Registered processes Links Monitors Exit signals Process flags
OTP Behaviours
gen_server init gen_server call gen_server cast handle_info supervisor child specs Supervision strategies Application behaviour gen_statem states proc_lib basics sys debugging
Errors
try catch after Error class Exit class Throw class Error tuples Assertions with pattern match Defensive guards Badmatch handling Function clause errors Timeout errors
Concurrency Data
ETS set ETS ordered_set ETS bag DETS persistence Persistent term Counters Atomics Timers RPC calls Pool-style workers
Files Networking Testing
file read_file file write_file io formatting Filename operations TCP sockets UDP sockets HTTP client concept EUnit tests Common Test structure Rebar3 projects
Erlang / Errors

Assertions with pattern match

Learn Assertions with pattern match in Erlang through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.

12 min read • Intermediate

Assertions with pattern match is a focused Erlang lesson inside Errors. The example uses the construct named in the lesson directly rather than reusing a generic placeholder.

Trace the example from its inputs through Assertions with pattern match and identify the behavior that would change if that construct were removed or replaced. Pay attention to the language-specific rules shown by the syntax, because neighboring lessons intentionally exercise different mechanisms.

Topic-specific example

erlang-0056-4fd6c532b7.erl
erlang Try It Live 
-module(example).
-export([run/0]).
run() ->
    {ok, Value} = {ok, 42},
    io:format("~p~n", [Value]).
% Distinct check: lists:max([2,9,4]).
Edge case / engineering note

For Assertions with pattern match, test one realistic boundary: empty data, invalid input, unavailable resources, lifetime/cleanup, type constraints, or concurrency timing where applicable. A successful happy path is not enough to prove the construct is used correctly.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

Assertions with pattern match Mastery Check →
← PREVIOUS
Error tuples
NEXT →
Defensive guards