ccdoc eval_expression ../fmutl/calc.h:82:function

FemtoScan Online SDK Documentation

function eval_expression

Evaluates expression.
Expression is a text string, containing:
real, decimal, hexadecimal (0x[0123456789abcdef]), octal (0[01234567]) numbers
constants:

false
0 value
true
1 value
m_pi
3.14159265358979323846 value
m_e
2.71828182845904523536 value

parentheses '(', ')'
comma ','
binary algebraical operators +, -, *, /, ^ (power)
binary boolean bitwise operators &, |, >>, <<
binary boolean operators !=, ==, &&, ||, >=, <=, >, <
unary operators ! (boolean not), - (negate)
functions from the list:
ln(x) - natural logarithm
log(x) - decimal logarithm
min(a,b) - minimum of two values
max(a,b) - maximum of two values
if(a,b,c) - if a!=0 then b else c
sgn(x) - if x>0 then 1.0, if x<0 then -1.0, if x==0 then 0.0
cal_tbl(double calibrating_value, string calibration_table) - returns double calibrated value, evaluated according to the calibration table. Calibration table should contain value-calibrated_value pairs, like this: "-3.0=27.0,3.0=60.0". This table will return calibrated value equal to 27.0 for -3.0 on input.
load_caltbl(string section_name, string path) - load calibration table from the file, located at given path, from given section. The section should contain value-calibrated value pairs, for example:
function call:
load_caltbl("temperature","temperature.ini")
temperature.ini file contents:
[temparature]
-3.0=27.0;
0.0=40.0;
3.0=60.0;
call_function([parameter[,parameter]...,]"[module:]function_name[@parameters_list][*free_function_name]") - returns string as a result of function call. Parameters can be double (marked as 'd' in parameters list) or string (marked 's') values.
interface() - has the same parameters as call_function, but when invoked, just clears the stack (i.e. performs nothing). This function should be used for custom interface implementation in SPMVarList class derivatives (for example, in fmcmnctl::CVarListCtrl class).
hex(x) when used as display string, in SPMVarList class will display an integer value in hexadecimal representation
strlistval(str,N) returns N's token of comma-delimiter list str
slrlistlimit(str,N) returns str with first N tokens
All unrecognized strings will be removed from expression.

Source:
../fmutl/calc.h:82

Author:
ATC

Version:
1.1

Params:

expr string containing expression to evaluate.

var result of evaluation.

len length of expression string (in case expression ends before the terminating zero), -1 if all the string is expression. -1 is by default.

Returns:
true if expression was evaluated, false if error was encountered.

See Also:
fmcmnctl::CVarListCtrl, SPMVarList::call_interface

Code:
public extern "C" FMUTL_API bool eval_expression ( const char * expr ,
SPMVar & var ,
int len = - 1 )

expr	string containing expression to evaluate.
var	result of evaluation.
len	length of expression string (in case expression ends before the terminating zero), -1 if all the string is expression. -1 is by default.

public extern "C" FMUTL_API bool eval_expression (	const char * expr ,
	SPMVar & var ,
	int len = - 1 )