From 88f9ce0ea625ff96b801db84097161ee0fead1dd Mon Sep 17 00:00:00 2001
From: Andre Wagner <WagnerAndre@JohnDeere.com>
Date: Wed, 6 May 2026 11:12:41 -0500
Subject: [PATCH] .

---
 lua-temp/TODO.md      |  4 ++--
 lua-temp/tests.lua    | 19 +++++++++++++++
 lua-temp/tyche-vm.lua | 55 ++++++++++++++++++++++++++++++++++++++-----
 3 files changed, 70 insertions(+), 8 deletions(-)

diff --git a/lua-temp/TODO.md b/lua-temp/TODO.md
index 7f64cee..283a45c 100644
--- a/lua-temp/TODO.md
+++ b/lua-temp/TODO.md
@@ -3,8 +3,8 @@ Progress of the Lua port:
 - [x] Assembler
 - [x] Basic VM execution
 - [x] Logic/arithmetic expressions
-- [ ] Variables
-  - [ ] Local variables
+- [x] Variables
+  - [x] Local variables
 - [ ] Functions
   - [ ] Calling functions
   - [ ] Calling functions with parameters
diff --git a/lua-temp/tests.lua b/lua-temp/tests.lua
index cc65f37..7476687 100644
--- a/lua-temp/tests.lua
+++ b/lua-temp/tests.lua
@@ -197,4 +197,23 @@ do TEST("VM: local variables")
     assert_eq(vm:to_integer(-1), 3)
 end
 
+do TEST("VM: functions")
+    local vm = VM:new():set_debug(true):load(assemble([[
+        .func 0
+            pushf   1
+            pushi   2
+            pushi   3
+            call    2
+            ret
+        .func 1
+            dupv    0
+            dupv    1
+            sum
+            ret
+    ]])):call(0)
+
+    assert_eq(vm:stack_sz(), 1)
+    assert_eq(vm:to_integer(-1), 5)
+end
+
 print('End.')
\ No newline at end of file
diff --git a/lua-temp/tyche-vm.lua b/lua-temp/tyche-vm.lua
index 9cc1782..c9f4e00 100644
--- a/lua-temp/tyche-vm.lua
+++ b/lua-temp/tyche-vm.lua
@@ -24,7 +24,20 @@ function format_value(v)
     elseif v.type == 'nil' then
         return 'nil'
     else
-        return pprint.format(v)
+        return pprint.pformat(v)
+    end
+end
+
+function validate_value(v)
+    assert(v, "value cannot be nil")
+    assert(type(v) == 'table', "invalid value format (expected { type='...', value=... }), received: " .. pprint.pformat(value))
+    assert(TYPE_MAP[v.type], "missing field 'type' in value")
+    if v.type == 'nil' then
+        assert(v.value == nil)
+    elseif v.type == 'number' then
+        assert(type(v.value) == 'number')
+    elseif v.type == 'function' then
+        assert(type(v.value) == 'number' and v.value >= 0, "function must be a positive number")
     end
 end
 
@@ -51,19 +64,18 @@ function Stack:top_fps()
 end
 
 function Stack:push(value)
-    assert(type(value) == 'table', "invalid value format (expected { type='...', value=... })")
-    assert(TYPE_MAP[value.type], "missing field 'type' in value")
+    validate_value(value)
     table.insert(self.stack, value)
 end
 
-function Stack:pop(value)
+function Stack:pop()
     if #self.stack < self:top_fps() then error("Stack underflow") end
     local v = self.stack[#self.stack]
     self.stack[#self.stack] = nil
     return v
 end
 
-function Stack:peek(value)
+function Stack:peek()
     if #self.stack < self:top_fps() then error("Stack underflow") end
     return self.stack[#self.stack]
 end
@@ -87,6 +99,7 @@ Stack.__index = function(self, key)
 end
 
 Stack.__newindex = function(self, key, value)
+    validate_value(value)
     local idx = tonumber(key)
     if idx then
         if idx >= 0 then
@@ -261,15 +274,34 @@ end
 --
 
 function VM:call(n_pars)
+    -- get parameters
+    local vars = {}
+    for i=1,n_pars do
+        vars[i] = self.stack:pop()
+    end
+
+    -- get function
     local f = self.stack:pop()
     if f.type ~= 'function' then error("Type error: expected function") end
+
+    -- enter function
     table.insert(self.loc, {
         f_id = f.value,
         pc = 1
     })
     self.stack:push_fp()
-    self:_run_until_return()  -- execute code
+
+    -- pass parameters
+    for i=1,n_pars do
+        self.stack:push(vars[#vars-i+1])
+    end
+
+    -- execute function
+    self:_run_until_return()
+
+    -- exit function
     table.remove(self.loc)
+
     return self
 end
 
@@ -293,20 +325,27 @@ function VM:_step()
     if op.operator == 'pushi' then
         self:push_integer(op.operand)
 
+    elseif op.operator == 'pushf' then
+        assert(op.operand >= 0)
+        self.stack:push({ type = 'function', value = op.operand })
+
     --
     -- local variables
     --
 
     elseif op.operator == 'pushv' then
+        assert(op.operand >= 0)
         for i=1,op.operand do
             self:push_nil()
         end
 
     elseif op.operator == 'set' then
+        assert(op.operand >= 0)
         local a = self.stack:pop()
         self.stack[op.operand + 1] = a
 
     elseif op.operator == 'dupv' then
+        assert(op.operand >= 0)
         local a = self.stack[op.operand + 1]
         self.stack:push(a)
 
@@ -323,6 +362,10 @@ function VM:_step()
     -- function management
     ---
 
+    elseif op.operator == 'call' then
+        assert(op.operand >= 0)
+        self:call(op.operand)
+
     elseif op.operator == 'ret' then
         local v = self.stack:pop()
         self.stack:pop_fp()