函数参数 #

function add(a, b)
    a + b
end

add(1, 2)

function power(base, exponent)
    base ^ exponent
end

power(2, 3)
power(3, 2)

function add(a::Int, b::Int)
    a + b
end

add(1, 2)
add(1.0, 2.0)

function greet(name, greeting="Hello")
    println("$greeting, $name!")
end

greet("Julia")
greet("Julia", "Hi")

function create_config(host="localhost", port=8080, debug=false)
    (host=host, port=port, debug=debug)
end

create_config()
create_config("example.com")
create_config("example.com", 443)
create_config("example.com", 443, true)

function process(data, timestamp=time())
    (data=data, timestamp=timestamp)
end

process("hello")

function process(a, b=a*2)
    (a=a, b=b)
end

process(5)
process(5, 20)

function create_point(x, y; color="red", size=1)
    println("Point($x, $y): color=$color, size=$size")
end

create_point(1, 2)
create_point(1, 2; color="blue")
create_point(1, 2; color="blue", size=5)

create_point(1, 2, color="blue")
create_point(1, 2; color="blue")

function process(; required)
    println("Required: $required")
end

process(required=10)
process()

function process(; x::Int=0, y::Float64=0.0)
    (x=x, y=y)
end

process()
process(x=10)
process(x=10, y=3.14)

function sum_all(args...)
    sum(args)
end

sum_all(1, 2, 3)
sum_all(1, 2, 3, 4, 5)
sum_all()

function process(first, rest...)
    println("First: $first")
    println("Rest: $rest")
end

process(1)
process(1, 2, 3, 4)

function sum_integers(args::Int...)
    sum(args)
end

sum_integers(1, 2, 3)
sum_integers(1, 2.0, 3)

function add_three(a, b, c)
    a + b + c
end

arr = [1, 2, 3]
add_three(arr...)

function process(; kwargs...)
    for (key, value) in kwargs
        println("$key = $value")
    end
end

process(a=1, b=2, c=3)

function process(; kwargs...)
    kwargs_dict = Dict(kwargs)
    haskey(kwargs_dict, :verbose) && println("Verbose mode")
    kwargs_dict
end

process(verbose=true, debug=false)

function process(required; default=10, kwargs...)
    println("Required: $required")
    println("Default: $default")
    println("Others: $kwargs")
end

process(1)
process(1, default=20)
process(1, default=20, extra=30)

function modify!(arr)
    push!(arr, 4)
end

arr = [1, 2, 3]
modify!(arr)
arr

function try_modify(x)
    x = 10
    return x
end

a = 5
try_modify(a)
a

function push_value!(arr, value)
    push!(arr, value)
end

arr = [1, 2, 3]
push_value!(arr, 4)

function flexible_sum(args...; ignore_negative=false)
    total = 0
    for x in args
        if ignore_negative && x < 0
            continue
        end
        total += x
    end
    return total
end

flexible_sum(1, 2, -3, 4)
flexible_sum(1, 2, -3, 4; ignore_negative=true)

function build_config(; name, version="1.0", kwargs...)
    config = Dict{Symbol, Any}(
        :name => name,
        :version => version
    )
    for (key, value) in kwargs
        config[key] = value
    end
    return config
end

build_config(name="MyApp", debug=true, port=8080)

function log_message(level, message; timestamp=time(), kwargs...)
    metadata = join(["$k=$v" for (k, v) in kwargs], ", ")
    println("[$level] $timestamp: $message ($metadata)")
end

log_message("INFO", "Server started"; host="localhost", port=8080)

function polynomial(x, coeffs...; normalize=false)
    result = 0.0
    for (i, c) in enumerate(coeffs)
        result += c * x^(i-1)
    end
    if normalize && length(coeffs) > 0
        result /= sum(coeffs)
    end
    return result
end

polynomial(2, 1, 2, 3)
polynomial(2, 1, 2, 3; normalize=true)