pattern

Pattern matching utilities for router path patterns

Supports various pattern types:

Static segments: “users”
Named parameters: “:id”
Single wildcards: “*” or “*name”
Multi-segment wildcards: “**” or “**path”
Extension patterns: “.jpg” or “.{jpg,png,gif}”

This is an internal module used by the router for path matching. Most applications won’t need to use this directly - the router handles pattern matching automatically.

Pattern Examples

// Static: /users/profile
// Param: /users/:id → extracts id
// Single wildcard: /files/* → matches one segment
// Multi wildcard: /files/** → matches multiple segments
// Extension: /images/*.jpg → matches .jpg files
// Multiple extensions: /images/*.{jpg,png,gif}

Types

PatternType

</>

Pattern segment type

Classifies what kind of pattern segment we’re matching against. Used internally by the pattern matcher to determine how to handle each segment of a route pattern.

Variants

StaticSegment: Exact match required (e.g., “users”)
ParamSegment: Named parameter (e.g., “:id”)
SingleWildcard: Matches one segment (e.g., “*” or “*name”)
MultiWildcard: Matches multiple segments (e.g., “**” or “**path”)
ExtensionPattern: Matches file extension (e.g., “*.jpg”)

pub type PatternType {
  StaticSegment
  ParamSegment
  SingleWildcard
  MultiWildcard
  ExtensionPattern
}

Constructors

```
StaticSegment
```
```
ParamSegment
```
```
SingleWildcard
```
```
MultiWildcard
```
```
ExtensionPattern
```

Values

match_segments

</>

pub fn match_segments(
  pattern_segments: List(String),
  path_segments: List(String),
) -> option.Option(List(#(String, String)))

Match a pattern against path segments and extract parameters

Core pattern matching function that compares a route pattern (split into segments) against a request path (also split into segments). Returns extracted parameters if the pattern matches, None if it doesn’t.

Parameters

pattern_segments: Route pattern split by “/” (e.g., [“users”, “:id”])
path_segments: Request path split by “/” (e.g., [“users”, “123”])

Returns

Some(params): List of extracted parameters as key-value tuples
None: Pattern doesn’t match the path

Examples

// Named parameter
match_segments(["users", ":id"], ["users", "123"])
// Some([#("id", "123")])

// Multiple parameters
match_segments(["users", ":user_id", "posts", ":id"], ["users", "1", "posts", "2"])
// Some([#("user_id", "1"), #("id", "2")])

// Wildcard
match_segments(["files", "**path"], ["files", "docs", "guide.pdf"])
// Some([#("path", "docs/guide.pdf")])

// No match
match_segments(["users", ":id"], ["posts", "123"])
// None