Bug #697: Interpreter: Avoid outputting an empty line after each line of input - CoCoA-5 - CoCoA Project

Bug #697

Interpreter: Avoid outputting an empty line after each line of input

Added by John Abbott almost 9 years ago. Updated over 6 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Anna Maria Bigatti

Category:

Parser/Interpreter

Target version:

CoCoA-5.2.2

Start date:

11 May 2015

Due date:

% Done:

100%

Estimated time:

1.01 h

Spent time:

0.75 h

Description

CoCoA-5 prints an empty line after each input line which outputs nothing.

Might be related to the fact that standalone expressions are equivalent to println <expr>?

Related issues

History

#1 Updated by John Abbott over 8 years ago

Priority changed from Normal to Low
Target version changed from CoCoA-5.1.2 summer 2015 to CoCoA-5.1.3/4 Jan 2016

This is just a cosmetic issue; so I have lowered the priorty, and postponed to next version of C5. I think it will involve some time-consuming understanding of the interpreter code; probably the actual fix will be fairly simple (once the code for the interpreter has been comprehended).

#2 Updated by John Abbott about 8 years ago

Target version changed from CoCoA-5.1.3/4 Jan 2016 to CoCoA-5.?.?

#3 Updated by Anna Maria Bigatti about 7 years ago

Assignee set to Anna Maria Bigatti
Priority changed from Low to Normal
Target version changed from CoCoA-5.?.? to CoCoA-5.2.2
% Done changed from 0 to 10

The line printing the newline is this, in LineProviders.H:

std::string promptHeader() const { return openBlocks.empty() ? "\n" : "\n"+openBlocks.back(); }

#4 Updated by John Abbott about 7 years ago

Perhaps the interpreter needs to have a flag saying whether a newline should be printed before printing the prompt.
The flag starts off as false, and it reset to false by the command println (which already prints a newline).
The command print sets the flag to true (unless the string it prints is empty?)

This heuristic does mean that there is a slight difference between println; and print "\n";
But I do not think that this is very important.