Tracing Joy Execution¶
joy.utils.pretty_print
¶
Pretty printing support, e.g.:
Joy? [23 18 * 99 +] trace
• 23 18 mul 99 add
23 • 18 mul 99 add
23 18 • mul 99 add
414 • 99 add
414 99 • add
513 •
513 <-top
joy?
On each line the stack is printed with the top to the left, then a bullet symbol,``•``, to represent the current locus of processing, then the pending expression to the right.
-
class
joy.utils.pretty_print.
TracePrinter
[source]¶ This is what does the formatting. You instantiate it and pass the
viewer()
method to thejoy.joy.joy()
function, then print it to see the trace.-
go
()[source]¶ Return a list of strings, one for each entry in the history, prefixed with enough spaces to align all the interpreter dots.
This method is called internally by the
__str__()
method.Return type: list(str)
-
viewer
(stack, expression)[source]¶ Record the current stack and expression in the TracePrinter’s history. Pass this method as the
viewer
argument to thejoy.joy.joy()
function.Parameters: - quote (stack) – A stack.
- expression (stack) – A stack.
-
-
joy.utils.pretty_print.
trace
(stack, expression, dictionary)[source]¶ Evaluate a Joy expression on a stack and print a trace.
This function is just like the i combinator but it also prints a trace of the evaluation
Parameters: - stack (stack) – The stack.
- expression (stack) – The expression to evaluate.
- dictionary (dict) – A
dict
mapping names to Joy functions.
Return type: (stack, (), dictionary)