6.8.7.4 Iterating with the do syntax

Syntax: do ?body (while ?test)

Syntax: do ?body (until ?test)

Auxiliary Syntax: while

Auxiliary Syntax: until

Auxiliary Syntax: continue

Auxiliary Syntax: break

These syntaxes extend the built–in do syntax as defined by R6RS.

For do ... (while ...):

• Evaluate ?body at least once, then: if the expression ?test evaluates to non–false loop.
• Using continue in the body cause a direct jump to the end of the current iteration, evaluating the ?test.
• Using the syntax break in the body causes immediate escaping out of the loop. A syntax use of break accepts no arguments.
• A use of this syntax returns no values.

For do ... (until ...):

• Evaluate ?body at least once, then if the expression ?test evaluates to false loop.
• Using continue in the body cause a direct jump to the end of the current iteration, evaluating the ?test.
• Using the syntax break in the body causes immediate escaping out of the loop. A syntax use of break accepts no arguments.
• A use of this syntax returns no values.

For the standard syntax:

• Using continue in the body cause a direct jump to the end of the current iteration, evaluating the ?test.
• Using the syntax break in the body causes immediate escaping out of the loop. A syntax use of break accepts no arguments.