[ecosSystem]

Problem

In a macro script, a codeblock cannot see the LOCALs of the script:

local a as array
local nL as dword
a := {1,2,4,3,5}
nL := 4
nPos := ascan(a, {|x| x = nL})   // runtime error: Variable does not exist: nL

Nested codeblocks are compiled as isolated DynamicMethods, so nL is unknown inside the block and is resolved at runtime as memvar/field. Scripts have to use PRIVATEs or __LocalPut()/__LocalsClear() instead. This case was already present in ScriptTests.prg under #ifdef FAIL.

Change

Nested codeblocks now capture locals of the enclosing script or codeblock, like the full compiler does:

• Lookup: when a nested binder can't find a name, it falls back to the locals of the enclosing binders, at any nesting depth (Binder.CaptureLocal). Memvars, fields, constants and arguments keep their existing late-bound resolution.
• Storage: a captured local is stored in a StrongBox<T> that the outer code and the codeblock share. Assignments inside the block are visible outside and vice versa.
• Instances: a capturing codeblock gets the signature (Codeblock[] nested, object[] env, T[] args). Each evaluation of the codeblock literal creates a new codeblock bound to the current boxes (ClosureTemplate / MacroClosure.Bind), so recursion and stored codeblocks behave correctly.
• Supporting fixes so captured variables also work as:
  • codeblock parameters: read from the args array by position, not by IL local index
  • CATCH variables: declared inside the catch block
  • FOREACH variables: the dispose code uses EmitGet

Codeblocks that don't use outer locals are compiled exactly as before.

Tests

• ScriptTests.prg: the former #ifdef FAIL test is enabled. New tests cover assigning a captured local, a parameter captured two levels deep, and a codeblock that sees later changes of the local.

• Harness: I also checked with a C# harness, in the VO and Core dialects, through both Compile (object) and CompileCodeblock (usual). The harness covers:

  • the script above
  • an assigning block and a typed local
  • two nesting levels and several captured locals
  • loop and CATCH variables
  • parameter shadowing
  • PRIVATE and __LocalPut as regression checks

  All cases fail with "Variable does not exist" before the change and pass after it.

• Real application: the change was tried in a real application that runs scripts through GetScriptCompiler() + CompileCodeblock().

Side note, not changed here: AEval() cannot be called from macros or scripts at all. It fails with XM0205 No suitable overload, with or without this change. That is being looked at separately.

🤖 Generated with Claude Code