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C++ Mathematical Expression Library (ExprTk) http://www.partow.net/programming/exprtk/index.html

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Arash Partow 2013-10-17 08:44:15 +11:00
parent f28fd418b5
commit 58c2b0805e
2 changed files with 48 additions and 13 deletions
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2
exprtk_simple_example_09.cpp
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@ -3,7 +3,7 @@
* C++ Mathematical Expression Toolkit Library * * C++ Mathematical Expression Toolkit Library *
* * * *
* Simple Example 9 * * Simple Example 9 *
* Author: Arash Partow (1999-2012) * * Author: Arash Partow (1999-2013) *
* URL: http://www.partow.net/programming/exprtk/index.html * * URL: http://www.partow.net/programming/exprtk/index.html *
* * * *
* Copyright notice: * * Copyright notice: *

59
readme.txt
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@ -5,7 +5,7 @@ The C++ Mathematical Expression Toolkit Library (ExprTk) is a simple
to use, easy to integrate and extremely efficient mathematical to use, easy to integrate and extremely efficient mathematical
expression parsing and evaluation engine. The parsing engine supports expression parsing and evaluation engine. The parsing engine supports
numerous forms of functional and logic processing semantics and is numerous forms of functional and logic processing semantics and is
very easily extendible. easily extendible.
@ -61,7 +61,7 @@ expressions that can be parsed and evaluated using the ExprTk library.
(12) (x + y)3.3 + 1 / 4.5 == (x + y) * 3.3 + 1 / 4.5 (12) (x + y)3.3 + 1 / 4.5 == (x + y) * 3.3 + 1 / 4.5
(13) (x + y)z + 1.1 / 2.7 == (x + y) * z + 1.1 / 2.7 (13) (x + y)z + 1.1 / 2.7 == (x + y) * z + 1.1 / 2.7
(14) (sin(x / pi) cos(2y) + 1) == (sin(x / pi) * cos(2 * y) + 1) (14) (sin(x / pi) cos(2y) + 1) == (sin(x / pi) * cos(2 * y) + 1)
(15) 25x^5 - 35x^4 - 15x^3 + 40x^2 - 15x + 1 (15) 75x^17 + 25.1x^5 - 35x^4 - 15.2x^3 + 40x^2 - 15.3x + 1
(16) if (avg(x,y) <= x + y, x - y, x * y) + 2.345 * pi / x (16) if (avg(x,y) <= x + y, x - y, x * y) + 2.345 * pi / x
(17) fib_i := fib_i + (x := y + 0 * (fib_i := x + (y := fib_i))) (17) fib_i := fib_i + (x := y + 0 * (fib_i := x + (y := fib_i)))
(18) while (x <= 100) { x := x + 1 } (18) while (x <= 100) { x := x + 1 }
@ -327,9 +327,9 @@ include path (e.g: /usr/include/).
| [r0:r1] | The closed interval [r0,r1] of the specified string. | | [r0:r1] | The closed interval [r0,r1] of the specified string. |
| | eg: Given a string x with a value of 'abcdefgh' then: | | | eg: Given a string x with a value of 'abcdefgh' then: |
| | 0. x[1:4] == 'bcde' | | | 0. x[1:4] == 'bcde' |
| | 1. x[ :5] == 'abcdef' | | | 1. x[ :5] == x[:5] == 'abcdef' |
| | 2. x[3: ] == 'cdefgh' | | | 2. x[3: ] == x[3:] =='cdefgh' |
| | 3. x[ : ] == 'abcdefgh' | | | 3. x[ : ] == x[:] == 'abcdefgh' |
| | 4. x[4/2:3+2] == x[2:5] == 'cdef' | | | 4. x[4/2:3+2] == x[2:5] == 'cdef' |
| | | | | |
| | Note: Both r0 and r1 are assumed to be integers, where | | | Note: Both r0 and r1 are assumed to be integers, where |
@ -354,7 +354,7 @@ include path (e.g: /usr/include/).
| | switch | | | switch |
| | { | | | { |
| | case x > (y + z) : 2 * x / abs(y - z); | | | case x > (y + z) : 2 * x / abs(y - z); |
| | case x < 3 : sin(x + y) | | | case x < 3 : sin(x + y); |
| | default : 1 + x; | | | default : 1 + x; |
| | } | | | } |
+----------+---------------------------------------------------------+ +----------+---------------------------------------------------------+
@ -389,7 +389,39 @@ include path (e.g: /usr/include/).
[09 - SPECIAL FUNCTIONS] [09 - COMPONENTS]
There are three primary components, that are specialized upon a given
numeric type, which make up the core of ExprTk. The components are as
follows:
1. Symbol Table exprtk::symbol_table<T>
2. Expression exprtk::expression<T>
3. Parser exprtk::parser<T>
(1) Symbol Table
A structure that is used to store references to variables, constants
and functions that are to be used within expressions.
(2) Expression
A structure that holds an AST for a specified expression and is used
to evaluate said expression. If a compiled Expression uses variables
or user defined functions, it will then also have an associated Symbol
Table, which will contain references to said variables, functions et
al.
(3) Parser
A structure which takes as input a string representation of an
expression and attempts to compile said input with the result being an
instance of Expression. If an error is encountered during the
compilation process, the parser will stop compiling and return an
error status code, with a more detailed description of the error(s)
and its location within the input provided by the 'get_error'
interface.
[10 - SPECIAL FUNCTIONS]
The purpose of special functions in ExprTk is to provide compiler The purpose of special functions in ExprTk is to provide compiler
generated equivalents of common mathematical expressions which can be generated equivalents of common mathematical expressions which can be
invoked by using the 'special function' syntax (eg: $f12(x,y,z) or invoked by using the 'special function' syntax (eg: $f12(x,y,z) or
@ -460,7 +492,7 @@ correctly optimize such expressions for a given architecture.
[10 - EXPRTK NOTES] [11 - EXPRTK NOTES]
(00) Precision and performance of expression evaluations are the (00) Precision and performance of expression evaluations are the
dominant principles of the ExprTk library. dominant principles of the ExprTk library.
@ -470,7 +502,7 @@ correctly optimize such expressions for a given architecture.
(03) Results of expressions that are deemed as being 'valid' are to (03) Results of expressions that are deemed as being 'valid' are to
exist within the set of Real numbers. All other results will be exist within the set of Real numbers. All other results will be
of the value Not-A-Number (NaN). of the value: Not-A-Number (NaN).
(04) Supported user defined types are numeric and string variables (04) Supported user defined types are numeric and string variables
and functions. and functions.
@ -532,7 +564,7 @@ correctly optimize such expressions for a given architecture.
[11 - SIMPLE EXPRTK EXAMPLE] [12 - SIMPLE EXPRTK EXAMPLE]
--- snip --- --- snip ---
#include <cstdio> #include <cstdio>
#include <string> #include <string>
@ -586,7 +618,10 @@ int main()
for (std::size_t i = 0; i < parser.error_count(); ++i) for (std::size_t i = 0; i < parser.error_count(); ++i)
{ {
error_t error = parser.get_error(i); error_t error = parser.get_error(i);
printf("Err: %02d Pos: %02d Type: [%s] Msg: %s Expr: %s\n", printf("Error: %02d Position: %02d "
"Type: [%s] "
"Message: %s "
"Expression: %s\n",
static_cast<int>(i), static_cast<int>(i),
static_cast<int>(error.token.position), static_cast<int>(error.token.position),
exprtk::parser_error::to_str(error.mode).c_str(), exprtk::parser_error::to_str(error.mode).c_str(),
@ -607,7 +642,7 @@ int main()
[12 - FILES] [13 - FILES]
(00) Makefile (00) Makefile
(01) readme.txt (01) readme.txt
(02) exprtk.hpp (02) exprtk.hpp