BREAK [-d] [-e] line-number [filename] [progname] [WHEN [-x|-env] conditional expression]
set a breakpoint at a line.

BREAK [-d] [-e] paragraph-name [filename] [progname] [WHEN [-x|-env] conditional expression]
set a breakpoint on a paragraph.

BREAK -l
list breakpoints.

[-d: disable the breakpoint]
[-e: enable the breakpoint]

when-phrase specifies a break condition

the conditional expression has the following format:

{ value1 >  value2 }
         >=
         <
         <=
         =
         !=
         
{ ! cond1          }

{ cond1  && cond2  }
         ||     

where value1 and value2 are variable names, arithmetical expressions or constants, cond1 and cond2 are conditional expressions

The string constants must be delimited by '"'. 

If the -env option is specified, the variable names must be related to environment variables.

If the -x option is specified, the constants must be hexadecimal strings.  

The supported arithmetical operators are +,-,*,/