dellingr 0.2.0

An embeddable, pure-Rust Lua VM with precise instruction-cost accounting
Documentation 
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-- Closure tests for the Lua VM
-- Our implementation properly captures upvalues by REFERENCE using open/closed upvalues.
-- This means modifications to captured variables propagate correctly.

-- Test 1: Basic closure capturing a local variable
local x = 10
local getX = function()
    return x
end
result1 = getX()
print("Test 1 - Basic closure capture: " .. tostring(result1 == 10))

-- Test 2: Closure modifies captured variable
-- With proper capture-by-reference, each increment actually modifies the counter.
local counter = 0
local increment = function()
    counter = counter + 1
    return counter
end
local a = increment()
local b = increment()
-- With capture-by-reference, a == 1 and b == 2
result2 = a == 1 and b == 2
print("Test 2 - Capture-by-reference semantics: " .. tostring(result2))

-- Test 3: Multiple closures capturing the same variable
local y = 5
local getY = function()
    return y
end
local doubleY = function()
    return y * 2
end
result3 = getY() == 5 and doubleY() == 10
print("Test 3 - Multiple closures: " .. tostring(result3))

-- Test 4: Nested closures (closure capturing another closure's upvalue)
local outer = 100
local makeGetter = function()
    local inner = 50
    local getter = function()
        return outer + inner
    end
    return getter
end
local g = makeGetter()
result4 = g() == 150
print("Test 4 - Nested closures: " .. tostring(result4))

-- Test 5: Counter factory
-- With proper capture-by-reference, each counter maintains its own state.
local makeCounter = function()
    local count = 0
    local inc = function()
        count = count + 1
        return count
    end
    return inc
end
local c1 = makeCounter()
local c2 = makeCounter()
local v1 = c1()
local v2 = c1()
local v3 = c2()
-- c1 returns 1, then 2; c2 returns 1 (independent counter)
result5 = v1 == 1 and v2 == 2 and v3 == 1
print("Test 5 - Counter factory: " .. tostring(result5))

-- Test 6: Two closures sharing the same upvalue
local makeCounter2 = function()
    local count = 0
    local inc = function()
        count = count + 1
        return count
    end
    local get = function()
        return count
    end
    return inc, get
end
local inc, get = makeCounter2()
local x1 = inc()  -- count becomes 1
local x2 = get()  -- should see count == 1
local x3 = inc()  -- count becomes 2
local x4 = get()  -- should see count == 2
result6 = x1 == 1 and x2 == 1 and x3 == 2 and x4 == 2
print("Test 6 - Shared upvalue between closures: " .. tostring(result6))

-- Test 7: do...end block upvalue capture
local f7
do
    local secret = 42
    f7 = function() return secret end
end
-- secret is out of scope, but f7 should still access it
result7 = f7() == 42
print("Test 7 - do...end block capture: " .. tostring(result7))

-- Test 8: While loop variable capture
local whileFuncs = {}
local i = 1
while i <= 3 do
    local capture = i
    whileFuncs[i] = function() return capture end
    i = i + 1
end
result8 = whileFuncs[1]() == 1 and whileFuncs[2]() == 2 and whileFuncs[3]() == 3
print("Test 8 - While loop capture: " .. tostring(result8))

-- Test 9: Generic for loop variable capture
local forFuncs = {}
local items = {"a", "b", "c"}
for k, v in ipairs(items) do
    local capture = v
    forFuncs[k] = function() return capture end
end
result9 = forFuncs[1]() == "a" and forFuncs[2]() == "b" and forFuncs[3]() == "c"
print("Test 9 - Generic for loop capture: " .. tostring(result9))

print("All closure tests complete!")