Improved history & highlighting

.vscode/settings.json

@@ -1,5 +1,6 @@
 {
     "cSpell.words": [
+        "appendleft",
         "autochurch",
         "delmac",
         "Endnodes",

README.md

@@ -48,6 +48,8 @@ There are many useful macros in [macros.lamb](./macros.lamb). Load them with the
 ==> :load macros.lamb
 ```
 
+You may use up/down arrows to recall history.
+
 Have fun!
 
 -------------------------------------------------
@@ -66,7 +68,12 @@ Lamb understands many commands. Prefix them with a `:` in the prompt.
 
 `:mdel [macro]` Delete a macro
 
-`:step [yes | no]` Enable or disable step-by-step reduction. Toggle if no argument is given.
+`:step [yes | no]` Enable or disable step-by-step reduction. Toggle if no argument is given. When reducing by steps, the prompt tells you what kind of reduction was done last:
+
+ - `M`: Macro expansion
+ - `C`: Church expansion
+ - `H`: History expansion
+ - `F`: Function application
 
 `:expand [yes | no]` Enable or disable full expansion. Toggle if no argument is given. If full expansion is enabled, ALL macros will be expanded when printing output.
 
@@ -81,7 +88,6 @@ The lines in a file look exactly the same as regular entries in the prompt, but
 
 
 ## Todo (pre-release, in this order):
- - History queue
  - Prevent macro-chaining recursion
  - Update screenshot
  - Update documentation
@@ -91,7 +97,6 @@ The lines in a file look exactly the same as regular entries in the prompt, but
 
 ## Todo:
  - Cleanup warnings
- - Syntax highlight printouts
  - Truncate long expressions in warnings
  - History indexing
  - Show history command

lamb/nodes/functions.py

@@ -162,14 +162,13 @@ def prepare(root: lbn.Root, *, ban_macro_name = None) -> list:
 	it = iter(root)
 	for s, n in it:
 		if isinstance(n, lbn.History):
-			if len(root.runner.history) == 0:
+			if root.runner.history[0] == None:
 				raise lbn.ReductionError("There isn't any history to reference.")
 			else:
 				warnings += [
 					("class:code", "$"),
-					("class:warn", " will be expanded to "),
-					("class:code", f"{n.expand()[1]}\n"),
-				]
+					("class:warn", " will be expanded to ")
+				] + lamb.utils.lex_str(str(n.expand()[1]))
 
 		# If this expression is part of a macro,
 		# make sure we don't reference it inside itself.

lamb/nodes/nodes.py

@@ -321,12 +321,12 @@ class History(ExpandableEndNode):
 	def expand(self) -> tuple[lbn.ReductionType, Node]:
 		# We shouldn't ever get here, prepare()
 		# catches empty history.
-		if len(self.runner.history) == 0:
+		if self.runner.history[0] == None:
 			raise Exception(f"Tried to expand empty history.")
 		# .left is VERY important!
 		# self.runner.history will contain Root nodes,
 		# and we don't want those *inside* our tree.
-		return lbn.ReductionType.HIST_EXPAND, lbn.clone(self.runner.history[-1].left)
+		return lbn.ReductionType.HIST_EXPAND, lbn.clone(self.runner.history[0].left)
 
 	def copy(self):
 		return History(runner = self.runner)

lamb/runner/commands.py

@@ -234,9 +234,8 @@ def cmd_load(command, runner):
 
 		printf(
 			FormattedText([
-				("class:ok", f"Loaded {x.label}: "),
-				("class:code", str(x.expr))
-			]),
+				("class:ok", f"Loaded {x.label}: ")
+			] + lamb.utils.lex_str(str(x.expr))),
 			style = lamb.utils.style
 		)
 

lamb/runner/runner.py

@@ -3,7 +3,7 @@ from prompt_toolkit.formatted_text import FormattedText
 from prompt_toolkit.key_binding import KeyBindings
 from prompt_toolkit import prompt
 from prompt_toolkit import print_formatted_text as printf
-import enum
+import collections
 import math
 import time
 
@@ -58,7 +58,10 @@ class Runner:
 		# so that all digits appear to be changing.
 		self.iter_update = 231
 
-		self.history: list[lamb.nodes.Root] = []
+		self.history = collections.deque(
+			[None] * 10,
+			10)
+
 
 		# If true, reduce step-by-step.
 		self.step_reduction = False
@@ -160,10 +163,9 @@ class Runner:
 				try:
 					s = prompt(
 						message = FormattedText([
-							("class:muted", lamb.nodes.reduction_text[red_type]),
-							("class:muted", f":{k:03} "),
-							("class:text", str(node)),
-						]),
+							("class:prompt", lamb.nodes.reduction_text[red_type]),
+							("class:prompt", f":{k:03} ")
+						] + lamb.utils.lex_str(str(node))),
 						style = lamb.utils.style,
 						key_bindings = step_bindings
 					)
@@ -218,9 +220,8 @@ class Runner:
 				only_macro
 		):
 			out_text += [
-				("class:ok", "\n\n    => "),
-				("class:text", str(node)), # type: ignore
-			]
+				("class:ok", "\n\n    => ")
+			] + lamb.utils.lex_str(str(node))
 
 
 		printf(
@@ -230,7 +231,12 @@ class Runner:
 
 		# Save to history
 		# Do this at the end so we don't always fully expand.
-		self.history.append(lamb.nodes.expand(node, force_all = True)[1])
+		self.history.appendleft(
+			lamb.nodes.expand( # type: ignore
+				node,
+				force_all = True
+			)[1]
+		)
 
 	def save_macro(
 			self,

lamb/utils.py

@@ -4,6 +4,7 @@ from prompt_toolkit.lexers import Lexer
 from prompt_toolkit.key_binding import KeyBindings
 from prompt_toolkit import print_formatted_text as printf
 from importlib.metadata import version
+from prompt_toolkit.document import Document
 
 import re
 
@@ -77,6 +78,10 @@ class LambdaLexer(Lexer):
 		return inner
 
 
+
+def lex_str(s: str) -> list[tuple[str, str]]:
+	return LambdaLexer().lex_document(Document(s))(0)
+
 def show_greeting():
 	#   |  _.._ _.|_
 	#   |_(_|| | ||_)