The Reflection module provides tools for runtime introspection and program analysis. From inspecting variables to benchmarking code, it offers comprehensive capabilities for understanding and analyzing your program's behavior.

Key Concepts

• Runtime information retrieval
• Symbol and attribute inspection
• Performance measurement
• Stack examination

Basic Usage

Inspecting Values

value: [1 2 #[name: "John"] [nested block]]

; detailed inspection
inspect value     ; shows full structure with types

; get information about function/symbol
info 'print      ; shows details about 'print function
info.get 'print  ; returns info as dictionary

; get current stack
print stack      ; shows current value stack (as a block)

Working with Attributes

doSth function [x][
    ; check if attribute exists
    if attr? 'verbose -> 
        print "verbose mode on"

    ; get attribute value
    level: attr 'level    ; returns null if not set

    ; get all attributes
    options: attrs        ; returns dictionary of all set attributes
]

Symbol Management

; get all defined symbols
syms: symbols       ; returns dictionary of all symbols

; check if symbol exists
print set? 'x       ; true if 'x is defined

; get function arity
funcs: arity        ; get dictionary of function arities

print arity\add     ; 2 (which is the number of parameters `add` takes ;-)) 

Performance Measurement

; basic benchmarking
benchmark [
    loop 1..1000 'x [
        ; some operation
    ]
]

; with the .get attribute
elapsed: benchmark.get [
    ; some operation
]
print ["Operation took:" elapsed]

; multiple runs for better accuracy
total: 0
loop 1..100 'run [
    'total ++ benchmark.get [
        ; operation to measure
    ]
]
average: total / 100

Common Patterns

Function Analysis

; get complete function information
analyzeFunction: function [funcName][
    info: info.get funcName
    
    print ["Function:" funcName]
    print ["Type:" info\type]
    print ["Arguments:" info\args]
    print ["Returns:" info\returns]
    if key? info 'options [
        print ["Options:" info\options]
    ]
]

analyzeFunction 'split
; Function: split 
; Type: :function 
; Arguments: [collection:[:string :literal :pathliteral :block]] 
; Returns: [:block :nothing] 

Performance Profiling

; simple profiling helper
profile: function [label operation][
    print ["Profiling:" label]
    
    ; multiple runs for stability
    times: []
    loop 1..10 'run [
        'times ++ to :floating benchmark.get operation
    ]
    
    ; calculate statistics
    avg: average times
    dev: deviation times
    
    print ["Average:" avg "±" dev "seconds"]
]

; usage example
profile "array sorting" [
    sort [5 3 8 1 9 2 7 4 6 0]
]

Runtime Information

; check execution context
if standalone? [
    ; very useful in the case of "importable" modules/packages
    ; or when you want to inject some tiny bit of testing code, etc...
    print "Running as standalone script"
]