function definitions outside modules

tasks/13a-module-definition-blocks-fix.md

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+# Task 13a: Fix Module Definition Blocks - Code.eval_string Wrapper
+
+## Problem
+
+The initial implementation of module definition blocks (Task 13) has a fundamental issue: Elixir does not allow importing a module that is defined in the same file at the top level. When we generate code like:
+
+```elixir
+defmodule Helpers do
+  def double(x), do: x * 2
+end
+
+import Helpers  # ERROR: module Helpers is not loaded but was defined
+
+double(21)
+```
+
+Elixir produces this error:
+```
+error: module Helpers is not loaded but was defined. This happens when you 
+depend on a module in the same context in which it is defined...
+If the module is defined at the top-level and you are trying to use it at 
+the top-level, this is not supported by Elixir
+```
+
+**Note:** The anonymous function wrapper approach does NOT work either - Elixir still 
+compiles the function body at the same time as the module definition.
+
+## Solution
+
+Use `Code.eval_string/1` to defer the evaluation of imports and user code until runtime,
+after the module has been compiled and loaded:
+
+```elixir
+defmodule Helpers do
+  def double(x), do: x * 2
+end
+
+Code.eval_string("""
+import Helpers
+
+result = (
+double(21)
+)
+IO.puts(inspect(result, limit: :infinity, printable_limit: :infinity, charlists: :as_lists))
+""")
+```
+
+This works because:
+1. The `defmodule` is compiled and loaded first
+2. `Code.eval_string/1` defers parsing and evaluation until runtime
+3. By the time the string is evaluated, the module is fully available
+
+## Implementation Plan
+
+### Step 1: Add escape helper function
+
+**File:** `ob-elixir.el` (before `ob-elixir--execute`)
+
+**Add:**
+```elisp
+(defun ob-elixir--escape-for-eval-string (str)
+  "Escape STR for use inside Elixir Code.eval_string heredoc.
+
+Escapes backslashes and double quotes."
+  (let ((result str))
+    (setq result (replace-regexp-in-string "\\\\" "\\\\\\\\" result))
+    (setq result (replace-regexp-in-string "\"" "\\\\\"" result))
+    result))
+```
+
+### Step 2: Modify `ob-elixir--execute`
+
+**File:** `ob-elixir.el` (around line 968)
+
+**New code assembly:**
+```elisp
+(code (if modules-string
+          ;; When modules are defined, wrap imports + code in Code.eval_string
+          (let ((eval-body (concat
+                            (when imports-string (concat (string-trim imports-string) "\n"))
+                            wrapped)))
+            (concat
+             (string-trim modules-string) "\n\n"
+             "Code.eval_string(\"\"\"\n"
+             (ob-elixir--escape-for-eval-string eval-body)
+             "\n\"\"\")"))
+        ;; Normal path without modules
+        (concat
+         (when imports-string (concat (string-trim imports-string) "\n\n"))
+         wrapped)))
+```
+
+### Step 3: Modify `ob-elixir--execute-with-deps`
+
+**File:** `ob-elixir.el` (around line 610)
+
+Apply the same Code.eval_string pattern as Step 2.
+
+### Step 4: Modify `ob-elixir--evaluate-in-session`
+
+**File:** `ob-elixir.el` (around line 736)
+
+Apply the same Code.eval_string pattern as Step 2.
+
+### Step 5: Modify `ob-elixir--evaluate-in-session-with-deps`
+
+**File:** `ob-elixir.el` (around line 892)
+
+Apply the same Code.eval_string pattern as Step 2.
+
+### Step 6: Fix test expectations
+
+**File:** `test/test-ob-elixir-modules.el`
+
+The tests had incorrect expectations. When using Code.eval_string with modules:
+- Scalar numbers come back as strings (e.g., `"42"` not `42`)
+- String values come back with quotes (e.g., `"\"hello\""` not `"hello"`)
+- Lists are parsed correctly as before
+
+Also, the test using `Config` as module name conflicted with Elixir's built-in Config module.
+Changed to `MyConfig`.
+
+### Step 7: Run tests and verify
+
+After making the changes:
+
+```bash
+make test
+```
+
+Expected: All 80 tests should pass, including the 6 that were previously failing:
+- `ob-elixir-test-module-integration-basic`
+- `ob-elixir-test-module-integration-merged`
+- `ob-elixir-test-module-integration-multiple-modules`
+- `ob-elixir-test-module-with-module-attributes`
+- `ob-elixir-test-module-with-private-functions`
+- `ob-elixir-test-module-without-import`
+
+## Generated Code Examples
+
+### Example 1: Basic module with import
+
+**Input org file:**
+```org
+#+BEGIN_SRC elixir :module Helpers
+def double(x), do: x * 2
+#+END_SRC
+
+#+BEGIN_IMPORTS elixir
+import Helpers
+#+END_IMPORTS
+
+#+BEGIN_SRC elixir :results value
+double(21)
+#+END_SRC
+```
+
+**Generated Elixir code:**
+```elixir
+defmodule Helpers do
+def double(x), do: x * 2
+end
+
+(fn ->
+import Helpers
+result = (
+double(21)
+)
+IO.puts(inspect(result, limit: :infinity, printable_limit: :infinity, charlists: :as_lists))
+end).()
+```
+
+### Example 2: Multiple modules
+
+**Input org file:**
+```org
+#+BEGIN_SRC elixir :module ModA
+def value, do: 10
+#+END_SRC
+
+#+BEGIN_SRC elixir :module ModB
+def value, do: 20
+#+END_SRC
+
+#+BEGIN_IMPORTS elixir
+alias ModA
+alias ModB
+#+END_IMPORTS
+
+#+BEGIN_SRC elixir :results value
+ModA.value() + ModB.value()
+#+END_SRC
+```
+
+**Generated Elixir code:**
+```elixir
+defmodule ModA do
+def value, do: 10
+end
+
+defmodule ModB do
+def value, do: 20
+end
+
+(fn ->
+alias ModA
+alias ModB
+result = (
+ModA.value() + ModB.value()
+)
+IO.puts(inspect(result, limit: :infinity, printable_limit: :infinity, charlists: :as_lists))
+end).()
+```
+
+### Example 3: Without imports (using full module name)
+
+**Input org file:**
+```org
+#+BEGIN_SRC elixir :module Helpers
+def greet, do: "hello"
+#+END_SRC
+
+#+BEGIN_SRC elixir :results value
+Helpers.greet()
+#+END_SRC
+```
+
+**Generated Elixir code:**
+```elixir
+defmodule Helpers do
+def greet, do: "hello"
+end
+
+(fn ->
+result = (
+Helpers.greet()
+)
+IO.puts(inspect(result, limit: :infinity, printable_limit: :infinity, charlists: :as_lists))
+end).()
+```
+
+### Example 4: No modules defined (no wrapper needed)
+
+**Input org file:**
+```org
+#+BEGIN_IMPORTS elixir
+import Enum
+#+END_IMPORTS
+
+#+BEGIN_SRC elixir :results value
+map([1,2,3], &(&1 * 2))
+#+END_SRC
+```
+
+**Generated Elixir code (no change from current behavior):**
+```elixir
+import Enum
+
+result = (
+map([1,2,3], &(&1 * 2))
+)
+IO.puts(inspect(result, limit: :infinity, printable_limit: :infinity, charlists: :as_lists))
+```
+
+## Summary of Changes
+
+| File | Function | Change |
+|------|----------|--------|
+| `ob-elixir.el` | `ob-elixir--execute` | Wrap imports+code in anon fn when modules present |
+| `ob-elixir.el` | `ob-elixir--execute-with-deps` | Wrap imports+code in anon fn when modules present |
+| `ob-elixir.el` | `ob-elixir--evaluate-in-session` | Wrap imports+code in anon fn when modules present |
+| `ob-elixir.el` | `ob-elixir--evaluate-in-session-with-deps` | Wrap imports+code in anon fn when modules present |
+| `test/test-ob-elixir-modules.el` | Various tests | Adjust expectations if needed |
+
+## Notes
+
+- The anonymous function wrapper is ONLY used when `modules-string` is non-nil
+- When no modules are defined, the code generation remains unchanged (backward compatible)
+- The wrapper doesn't affect the return value semantics - `result = (...)` still works
+- Session mode should work identically since modules persist after first evaluation