Chapter 23
Notations

This chapter introduces the various notations that are used in the document.

23.1 Words

• name
  Depending on the context, a variable name (i.e., an identifier in C ++ or urbiscript), or a meta-variable name. A meta-variable denotes a place where some syntactic construct may be entered. For instance, in while (expression) statement, expression and statement do not denote two variable names, but two placeholders which can be filled with an arbitrary expression, and an arbitrary statement. For instance:

  while (!tasks.empty) { tasks.removeFront.process }.

• name
  An environment variable name, e.g., PATH.
• code
  A piece of urbiscript or C ++ code.
• ‘name’
  A file name.

23.2 Frames

23.2.1 Shell Sessions

Interactive sessions with a (Unix) shell are represented as follows.

 
$ echo toto 
toto
   

The user entered ‘echo toto’, and the system answered ‘toto’. ‘$’ is the prompt: it starts the lines where the system invites the user to enter her commands.

23.2.2 urbiscript Sessions

Interactive sessions with Urbi are represented as follows.

 
echo(
"toto"
); 
[00000001] *** toto
   

Contrary to shell interaction (see Section 23.2.1), there is no prompt that marks the user-entered lines (here echo("toto");, but, on the contrary, answers from the Urbi server start with a label that includes a timestamp (here ‘00000001’), and possibly a channel name, ‘output’ in the following example.

 
cout << 
"toto"
; 
[00000002:output] "toto"
   

23.2.3 urbiscript Assertions

urbiscript features assertions blocks, see Section 19.8. The following assertion frame:

 
1 == 2 / 2; 
1 < 2; 
true; 
"foobar"
[0, 3] == 
"foo"
; 
[1, 2, 3].map (function (a) { a * a }) == [1, 4, 9]; 
[ => ].empty;
   

actually denotes the following assertion-block in an urbiscript-session frame:

 
assert 
{ 
  true; 
  1 < 2; 
  1 + 2 * 3 == 7; 
  
"foobar"
[0, 3] == 
"foo"
; 
  [1, 2, 3].map (function (a) { a * a }) == [1, 4, 9]; 
  [ => ].empty; 
};
   

23.2.4 C ++ Code

C++ source code is presented in frames as follows.

 
class Int 
{ 
public: 
  Foo(int v = 0) 
    : val_(v) 
  {} 
 
  void operator(int v) 
  { 
    std::swap(v, val_); 
    return v; 
  } 
 
  int operator() const 
  { 
    return val_; 
  } 
 
private: 
  int val_; 
};