EXP¶
exp - a multiple expession calculator.
SYNOPSIS¶
exp [
-vn
0..4] [
-o output-file]
[
input-file]
DESCRIPTION¶
Input is an ascii format file including numeric expessions with variables. Input
file can includes other input files thanks to an inclusion directive.
exp reads the input files to write it as is in the output file, but the
numeric expessions are replaced by their value.
OPTIONS¶
- -v
- verbose mode
0 : quiet mode
1 : messages mess(...) are printed
2 : few statistics
3 : all expressions are decomposed
4 : yacc messages
- -o output-file
- where exp writes (stdout by default).
- input-file
- where exp reads (stdin by default).
Except the expessionsi and offline comments, the output file is identical to the
flattened view of the input files whatever they are. The expession forms can
be either
[expessions] or
{expessions}. The first form is for
floating point expessions, the second one is for integer expessions. By
default, the print format is respectively %7.3f and %4d (cf.
sprintf(3)). Offline comments begins with // and ends at the beginning
of the next line.
Examples
- •
- [ 3.0 + 12.1] print 15.100
- •
- { 3.0 + 12.1} print 15
It is possible to have more that one expession separated by
;
(semi-column). All the expessions of a list are computed, but only the last
one is printed. If the last expession is empty,
exp do not print
anything (see Examples section).
Examples
- •
- [ 6. *2.0;
3.0 + 12.1 ] print 15.100
- •
- [ 6. *2.0;
3.0 + 12.1; ] print nothing
It is possible to have comments in expessions. A comment begins with
#
(diese) and ends to the carriage return. Comment in expression is not copied
to the output file.
Example
- •
- [ 3.0 + 12.1 # comment
] print 15.100
Expessions¶
Expession is a multi-level numeric expession using numbers, variables,
arithmetic operators and numeric functions.
Examples
- •
- [ i=3.0; i*12.1] print 15.100
- •
- {i=3} print 3
{i++} print 4
Arithmetic Operators¶
The operators, in order of increasing priority, are
- + -
- Addition and subtraction.
- * /
- Multiplication and division.
- ++ --
- post-incrementation of 1, post-decrementation of 1.
- ( )
- Grouping
- =
- Variable affectation. The return value is the one affected.
Boolean Operators¶
- > <
- respectively greater than and lower than
- def(variable)
- True whenever variable is defined yet
- ndef(variable)
- True whenever variable is not defined yet
Variables¶
Expession values may be stored in simple variables. There are three forms of
variable name. First, they can begin with a letter followed by any number of
letters, digits and underscores; second, they can begin with
"
(double quote) followed by any number of any char and ended by a
"; Third they can begin with
´ (quote) then a
regular expression (see
regex(7)) ended by
´.
exp
is case sensitive.
Examples
- •
- [ VAR_1=3.0; # first form
"variable numero 2"=12.0; # second form
] print nothing
- •
- [ VAR_1 * "variable numero 2" ] print 15.100
When a variable appears in the right member of an affectation,
exp uses
its value. If it has never been defined, this causes a fatal error. If it
appears the left member, the first time it is automatically created and its
value is set, or its value is changed.
Special variables¶
float_fmt,
integer_fmt and
string_fmt special variables to
redefine print format of floats, integers and strings. Defaults are %7.3f,
%-8s and %4d. Those variables are the only variables with a non numerical
value.
Examples
- •
- [float_fmt = "%7.1f";] print nothing
- •
- [ 3.0 + 12.1] print 15.1
verbose is the variable passed in argument list, which can be modified by
the program itself.
Examples get details of expression calculation
- •
- [tmp = verbose; verbose = 3; ..expressions..;
verbose = tmp;]
Numeric functions¶
Few numeric functions are available. The form is
fun(args). The arguments
take the form of a list of expessions, separated with a
, (comma). The
number of arguments depends on functions. It is possible to make a list of
arguments with a regular expession (see
regex(7)). Then all matching
variable names are part of the list.
- min(args) max(args)
- The minimum (resp. maximum) value of its arguments.
Examples
- •
- [min(3.0,12.1)] print 3.000
- •
- [min('RW_ALU.*')] print min value of all variables begining by
RW_ALU
- inf(step,val) sup(step,val)
- Two arguments. inf (resp. sup) function rounds the second
argument (val) downwards (resp. upwards) to an integer number of the first
argument (step).
Examples
- •
- [step=0.3;value=1.6;inf(step,value)] print 1.500
Special functions and directives¶
- if(condition, expr1, expr2, ...)
- Calculates the condition if it is true (means greater than zero), the
following expressions are all calculated.
- sort(args) rsort(args)
- sort (resp. reverse rsort) numerically all its arguments,
each argument must be a variable, not directly a numeric expession. The
return value is the sorted list of its arguments.
- message(args)
- writes its arguments to stdout using float_fmt, one argument per
line. The form is : variable_name = value;, value is omitted if the
variable has never been defined.
Examples
- •
- [message('"'this is a message'"');] print
this is a message
- •
- [a1b=0; a2b=1O; a3b=5; message(a*b);] print
a1b = 0.000
a2b = 1O.000
a3b = 5.000
- •
- [string_fmt=%6s; message(sort(a*b));] print
a1b = 0.000
a3b = 5.000
a2b = 1O.000
- #include "filename"
- Opens the file in argument then returns to the current file as soon as the
new one is empty.
EXAMPLES¶
- Input file
-
# this is a test file
[ # few variables
WITDH = 2;
LENGTH = 25 ;
]
this message is unchanged but all expresions are computed
length_div_2 = [LENGTH/2]
length_mul_2 = {LENGTH*2}
result = [max ('leng.*')]
- Output file
-
# this is a test file
this message is unchanged but all expresions are computed
length_div_2 = 12.500
length_mul_2 = 50
result = 12.500
AUTHOR¶
Written by Franck Wajsburt.
SEE ALSO¶
Alliance .rds file uses
exp to be generated.