bs(1) |
| bs(1) |
stop | Execution of internal statements is stopped. bs reverts to immediate mode. | |
trace [expression] |
| |
| The | trace statement controls function tracing. If the expression is null (or evaluates to |
| zero), tracing is turned off. Otherwise, a record of | |
| Each | return decrements the trace expression value. |
while expression statement while expression
... | while is similar to for except that only the conditional expression for |
next | |
| is given. |
!shell command
An immediate escape to the shell.
# ... | This statement is ignored (treated as a comment). |
Expression Syntax:
name A name is used to specify a variable. Names are composed of a letter (uppercase or lower- case) optionally followed by letters and digits. Only the ®rst six characters of a name are signi®cant. Except for names declared in fun statements, all names are global to the pro- gram. Names can take on numeric (double ¯oat) values, string values, or can be associated with input/output (see the
name ( [expression [ , expression] ... ] )
Functions can be called by a name followed by the arguments in parentheses separated by commas. Except for
name [ expression [ , expression ] ... ]
This syntax is used to reference either arrays or tables (see
number | A number is used to represent a constant value. A number is written in Fortran style, and |
| contains digits, an optional decimal point, and possibly a scale factor consisting of an e fol- |
| lowed by a possibly signed exponent. |
string | Character strings are delimited by " characters. The \ escape character allows the double |
| quote (\"), |
| appear in a string. Otherwise, \ stands for itself. |
( expression ) | Parentheses are used to alter the normal order of evaluation. |
( expression , expression [ , expression ... ] ) [ expression ]
The bracketed expression is used as a subscript to select a
| The expression: |
| ( False, True )[ a == b ] |
| has the value True if the comparison is true. |
? expression | The interrogation operator tests for the success of the expression rather than its value. At |
| the moment, it is useful for testing |
| tion below), the result of the eval |
| |
| immediate transfer to the most recent interrogation, possibly skipping assignment state- |
| ments or intervening function levels. |
- expression | The result is the negation of the expression. |
b
− 3 − | Section 1−51 |