Control Flow

Mux provides familiar control flow constructs with some unique features like pattern matching with guards.

If / Else

Standard if-else branching with curly braces:

if_else.mux

If as an Expression

In Mux, if can be used as an expression that returns a value:

if_expression.mux

For Loops

Mux uses range-based for loops only (no C-style for (int i = 0; i < n; i++)):

for_loops.mux

Ignoring Loop Variables

Use _ when you don't need the loop variable:

ignoring_loop_vars.mux

Iterating Collections

iterating_collections.mux

While Loops

Standard while loops with boolean conditions:

while_loops.mux

Break and Continue

Control loop execution:

break_continue.mux

Match Statements

Pattern matching with guards and destructuring:

Basic Matching

basic_matching.mux

This is equivalent to:

if_else_equivalent.mux

Matching optional

matching_optional.mux

Matching result

matching_result.mux

Pattern Matching with Guards

Guards add conditional logic to patterns:

pattern_guards.mux

Ignoring Values in Patterns

Use _ to ignore parts of patterns you don't need:

pattern_ignore.mux

Matching Enums

matching_enums.mux

Wildcard Pattern

The _ pattern matches anything:

wildcard_pattern.mux

Exhaustive Matching

Mux requires that all possible cases are handled in a match statement. If you miss a case, the compiler will give an error:

exhaustive_matching.mux

Match as Switch Statement

Match statements can be used as switch statements for any type, not just enums:

switch_on_primitives.mux

Variable Binding in Switch Patterns

Capture matched values in variables:

switch_variable_binding.mux

Constants in Switch Patterns

Use constants as match patterns:

switch_constants.mux

List Literal Matching

Match on list structure:

switch_list_matching.mux

Switch with Guards

Add conditions to switch cases:

switch_with_guards.mux

Return Statement

Exit a function early:

return_statement.mux

Best Practices

Use use for sequential propagation - It extracts the success value and returns the enclosing function's err/none without nested matches
Use inspection methods for local handling - Check is_ok()/is_err() or is_some()/is_none() before calling value() or error()
Prefer pattern matching with guards - Cleaner than nested if statements
Use _ for unused values - Makes intent explicit
Early returns for error conditions - Reduces nesting
Use range() for numeric loops - Idiomatic Mux
Break and continue judiciously - Can make code harder to follow if overused

If / Else​

If as an Expression​

For Loops​

Ignoring Loop Variables​

Iterating Collections​

While Loops​

Break and Continue​

Match Statements​

Basic Matching​

Matching optional​

Matching result​

Pattern Matching with Guards​

Ignoring Values in Patterns​

Matching Enums​

Wildcard Pattern​

Exhaustive Matching​

Match as Switch Statement​

Variable Binding in Switch Patterns​

Constants in Switch Patterns​

List Literal Matching​

Switch with Guards​

Return Statement​

Best Practices​

See Also​