Merge pull request #50 from glpython-edu/feature/unary-minus-name

Visualizer: no step for -x where it reads as its value; console check without buttons

Author: cedricvogel-leo

CLAUDE.md

@@ -55,7 +55,7 @@ There is no unit test framework. The automated checks are `test:protocol` (plain
   - Values are shown through `_glpython_safe_repr`, which writes types as learners do (`int`, not `<class 'int'>`); the program's own output keeps Python's repr.
   - It abbreviates long values (`[1, 2, 3, 4, 5, …, 100]`; levels in `_GLPYTHON_ABBREVIATION_LEVELS`) and notes each full text. The next recorded step gets `fullValues` (`{shown text: index}`), the trace result `values` (`{text, cut, length, kind}`). The UI (`fullValuesUpTo`, `ValueText`, `LocalsValue`, `FullValueDialog`) opens one on click.
   - A name indexed in a subscript (`dauer` in `dauer[1]`, `_glpython_indexed`) gets no step of its own, so `dauer[1]` is one step to the element.
-  - A display (`[…]`, `(…)`, `{…}`) gets no step of its own (`_glpython_record_display`), only where its value reads differently (unpacking, duplicates); nor does a negative number literal (`_glpython_is_negative_number`). Every step must change something.
+  - A display (`[…]`, `(…)`, `{…}`) gets no step of its own (`_glpython_record_display`), only where its value reads differently (unpacking, duplicates); nor does a negative number literal (`_glpython_is_negative_number`), or `-name` where it already reads as its value. Every step must change something.
 
 Worker messages:
 - `run` → `result`/`error`; while it runs, `output` messages (`{id, text}`, `id` undefined for a program, the input's id for a REPL input) stream what was printed, at most 50 per 50 ms. The final message brings the whole output again.

README.md

@@ -142,7 +142,9 @@ no steps at all, nested at any depth and with negative numbers (`-3`, `-2.5`):
 only the parts that change have steps: `[1 + 2, 3, 4] → [3, 3, 4]`,
 `["+", 1, ["*", n, 3]] → ["+", 1, ["*", 2, 3]]`. A display keeps its step only
 where its value reads differently: unpacking (`[*a, 2] → [1, 2]`) and a set or
-dict whose duplicates go (`{1, 1} → {1}`).
+dict whose duplicates go (`{1, 1} → {1}`). Likewise `-x` with `x = 7` is one
+step, to `-7`; the minus has a step of its own only where it changes what is
+shown (`-x` with `x = -7` reads `--7`, then `7`).
 
 A long value is abbreviated, in the step and in the variables panel alike,
 keeping its first elements and its last one: `[1, 2, 3, 4, 5, …, 100]`.

scripts/check-console-browser.mjs

@@ -167,7 +167,15 @@ try {
     await page.waitForFunction(() => window.ready, null, { timeout: 120000 })
     return page
   }
-  const consoleText = (frame) => frame.locator('.console').innerText()
+  // The transcript as it reads, without the entries' Visualize buttons: next
+  // to a ">>>" line or on a line of their own, depending on the width.
+  const consoleText = (frame) => frame.locator('.console').evaluate((console) => {
+    const buttons = [...console.querySelectorAll('.repl-entry-visualize')]
+    for (const button of buttons) button.style.display = 'none'
+    const text = console.innerText
+    for (const button of buttons) button.style.display = ''
+    return text
+  })
   const programLine = (frame) => frame.locator('.repl-line--program .repl-input')
   // A REPL input, once the REPL is free again (until then it keeps the text).
   const enterRepl = async (frame, text) => {

scripts/check-runtime-lists.py

@@ -121,13 +121,26 @@ def steps_on_line(result, line):
     ("a = 5", "w = [a, 2]", [("a", "5")], "[5, 2]"),
     ("x = 7", "w = [[1, 2], x]", [("x", "7")], "[[1, 2], 7]"),
     ("n = 2", 'w = ["+", 1, ["*", n, 3]]', [("n", "2")], "['+', 1, ['*', 2, 3]]"),
-    ("n = 2", "w = (n, -n, {n: [n]})", [("n", "2"), ("n", "2"), ("-2", "-2"), ("n", "2"), ("n", "2")], "(2, -2, {2: [2]})"),
+    ("n = 2", "w = (n, -n, {n: [n]})", [("n", "2"), ("n", "2"), ("n", "2"), ("n", "2")], "(2, -2, {2: [2]})"),
     ("", "w = [len([1, 2]), 3]", [("len(...)", "2")], "[2, 3]"),
 ]:
     result = trace(f"{setup}\n{line}\n")
     expect(f"one step each: {line}", evals_on_line(result, 2), expected)
     expect(f"the assignment: {line}", [label for kind, label, _ in steps_on_line(result, 2) if kind == "exec"], [f"w = {value}"])
 
+# "-x" is one step, to x's value, where that already reads as the result;
+# where it doesn't ("--7", "-True", "-(a + b)"), the minus has its step.
+for setup, line, expected in [
+    ("x = 7", "w = -x", [("x", "7")]),
+    ("x = 2.5", "w = -x", [("x", "2.5")]),
+    ("x = -7", "w = -x", [("x", "-7"), ("--7", "7")]),
+    ("x = True", "w = -x", [("x", "True"), ("-True", "-1")]),
+    ("a = 1\nb = 2", "w = -(a + b)", [("a", "1"), ("b", "2"), ("1 + 2", "3"), ("-3", "-3")]),
+]:
+    result = trace(f"{setup}\n{line}\n")
+    row = setup.count("\n") + 2
+    expect(f"unary: {setup}; {line}", evals_on_line(result, row), expected)
+
 # Where the value reads differently from the display, the display has its
 # step: unpacking, and duplicates in a set or dict. Unpacking as in Python.
 for setup, line, expected in [

src/runtime/visualizer.py

@@ -611,7 +611,13 @@ def _eval_unaryop(node, scope):
   if _glpython_is_negative_number(node):
     return value
   symbol = _GLPYTHON_OP_SYMBOLS.get(type(node.op), "?")
-  _glpython_record(node, "eval", f"{symbol}{_glpython_safe_repr(operand, 40)}", _glpython_safe_repr(value), _glpython_current_func())
+  text = f"{symbol}{_glpython_safe_repr(operand, 40)}"
+  value_text = _glpython_safe_repr(value)
+  # "-x" with x = 7 already reads "-7" once x is replaced: no step that
+  # changes nothing (but "-x" with x = -7 reads "--7", which becomes 7).
+  if isinstance(node.op, ast.USub) and isinstance(node.operand, ast.Name) and text == value_text:
+    return value
+  _glpython_record(node, "eval", text, value_text, _glpython_current_func())
   return value
 
 def _eval_boolop(node, scope):