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https://github.com/ws-garcia/VBA-Expressions

A powerful string expression evaluator for VBA and LO Basic, which puts more than 100 mathematical, statistical, financial, date-time, logic and text manipulation functions at the user's fingertips.
https://github.com/ws-garcia/VBA-Expressions

basic cholesky-decomposition cholesky-factorization curve-fitting determinant-calculation equation-systems libreoffice lo-basic lu-decomposition mathematical-expression-parser mathematical-expressions-evaluator mathematics maths matrix-multiplication multivariate-linear-regression science statistical-models

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A powerful string expression evaluator for VBA and LO Basic, which puts more than 100 mathematical, statistical, financial, date-time, logic and text manipulation functions at the user's fingertips.

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README

        

# VBA Expressions
## ![VBA Expressions](/docs/assets/img/VBA%20Expressions-NewLogo.png)
[![GitHub](https://img.shields.io/github/license/ws-garcia/VBA-Expressions?style=plastic)](https://github.com/ws-garcia/VBA-Expressions/blob/master/LICENSE) [![GitHub release (latest by date)](https://img.shields.io/github/v/release/ws-garcia/VBA-Expressions?style=plastic)](https://github.com/ws-garcia/VBA-Expressions/releases/latest) [![Mentioned in Awesome VBA](https://awesome.re/mentioned-badge.svg)](https://github.com/sancarn/awesome-vba)

## Introductory words
VBA Expressions is a powerful string expression evaluator for VBA and [LO Basic](https://extensions.libreoffice.org/en/extensions/show/70059), which puts more than 100 mathematical, statistical, financial, date-time, logic and text manipulation functions at the user's fingertips. The `VBAexpressions.cls` class mediates almost all VBA functions as well as custom functions exposed through it.

Although the main development goal of the class was the integration with [CSV Interface](https://github.com/ws-garcia/VBA-CSV-interface), VBA Expressions has evolved to become a support tool for students and teachers of science, accounting, statistics and engineering; this due to the added capability to solve systems of equations and non-linear equations in one variable.

## ![User Manual](/docs/assets/img/VBAExprManual.pdf)

## Advantages
* __Easy to use and integrate__.
* __Basic math operators__: `+` `-` `*` `/` `\` `^` `!`
* __Logical expressions__: `&` (AND), `|` (OR), `||` (XOR)
* __Binary relations__: `<`, `<=`, `<>`, `>=`, `=`, `==`, `>`, `$` (LIKE)
* __Outstanding matrix and statistical functions__: `CHOLESKY`, `MLR` (Multivariate Linear Regression), `FIT` (Curve fitting), `INVERSE`, and a lot more!
* __More than 100 built-in functions__: `Max`, `Sin`, `IRR`, `GAUSS`, `LSQRSOLVE`, `Switch`, `Iff`, `DateDiff`, `Solve`, `fZero`, `Format`...
* __Very flexible and powerful__: variables, constants and user-defined functions (UDFs) support.
* __Implied multiplication for variables, constants and functions__: `5avg(2;abs(-3-7tan(5));9)`, `5(x)` and `x(2)(3)` are valid expressions.
* __Evaluation of arrays of expressions given as text strings, as in Java__: curly brackets must be used to define arrays`{{...};{...}}`
* __Floating point notation input support__: `-5E-5`, `(1.434E3+1000)*2/3.235E-5` are valid inputs.
* __Free of external VBA dependencies__: does not use dll.

## Supported expressions

The evaluation approach used is similar to the one we humans use: divide the function into sub-expressions, create a symbolic string to build an expression evaluation flow, split the sub-expressions into chunks of operations (tokens) by tokenization, evaluate all the tokens.

The module can evaluate mathematical expressions such as:

+ `5*avg(2;abs(-3-7*tan(5));9)-12*pi-e+(7/sin(30)-4!)*min(cos(30);cos(150))`
+ `min(cos(sin(30))+2^2;1)`
+ \* `GCD(1280;240;100;30*cos(0);10*DET({{sin(atn(1)*2); 0; 0}; {0; 2; 0}; {0; 0; 3}}))`

\*`GCD` is an user-defined function (UDF).

Allowed expressions must follow the following grammar:

```
Expression = ([{"("}] SubExpr [{Operator [{"("}] SubExpr [{")"}]}] [{")"}] | {["("] ["{"] List [{";" List}] ["}"] [")"]})
SubExpr = Token [{Operator Token}]
Token = [{Unary}] Argument [(Operator | Function) ["("] [{Unary}] [Argument] [")"]]
Argument = (List | Variable | Operand | Literal)
List = ["{"] ["{"] SubExpr [{";" SubExpr}] ["}"] ["}"]
Unary = "-" | "+" | ~
Literal = (Operand | "'"Alphabet"'")
Operand = ({Digit} [Decimal] [{Digit}] ["E"("-" | "+"){Digit}] | (True | False))
Variable = Alphabet [{Decimal}] [{(Digit | Alphabet)}]
Alphabet = "A-Z" | "a-z"
Decimal = "." | ","
Digit = "0-9"
Operator = "+" | "-" | "*" | "/" | "\" | "^" | "%" | "!" | "<" | "<=" | "<>" | ">" | ">=" | "=" | "$" | "&" | "|" | "||"
Function = "abs" | "sin" | "cos" | "min" |...|[UDF]
```

## Operators precedence
VBA expressions uses the following precedence rules to evaluate mathematical expressions:

1. `()` Grouping: evaluates functions arguments as well.
2. `! - +` Unary operators: exponentiation is the only operation that violates this. Ex.: `-2 ^ 2 = -4 | (-2) ^ 2 = 4`.
3. `^` Exponentiation: Although Excel and Matlab evaluate nested exponentiations from left to right, Google, mathematicians and several modern programming languages, such as Perl, Python and Ruby, evaluate this operation from right to left. VBA expressions also evals in Python way: a^b^c = a^(b^c).
4. `\* / % ` Multiplication, division, modulo: from left to right.
5. `+ -` Addition and subtraction: from left to right.
6. `< <= <> >= = == > $` Binary relations.
7. `~` Logical negation.
8. `&` Logical AND.
9. `||` Logical XOR.
10. `|` Logical OR.

## Variables
Users can enter variables and set/assign their values for the calculations. Variable names must meet the following requirements:
1. Start with a letter.
2. End in a letter or number. `"x.1"`, `"number1"`, `"value.a"` are valid variable names.
3. A variable named `"A"` is distinct from another variable named `"a"`, since variables are case-sensitive. This rule is broken by the constant `PI`, since `PI=Pi=pi=pI`.
4. The token `"E"` cannot be used as variable due this token is reserved for floating point computation. For example, the expression `"2.5pi+3.5e"` will be evaluated to `~17.3679680`, but a expression like `"2.5pi+3.5E"` will return an error.

## User-defined functions (UDF)
Users can register custom modules to expose and use their functions through the VBAcallBack.cls module. All UDFs must have a single Variant argument that will receive an one-dimensional array of strings (one element for each function argument).

Here is a working example of UDF function creation
```
Sub AddingNewFunctions()
Dim Evaluator As VBAexpressions
Dim UDFnames() As Variant
Dim Result As String

Set Evaluator = New VBAexpressions
UDFnames() = Array("GCD")
With Evaluator
.DeclareUDF UDFnames, "UserDefFunctions" 'Declare the Greatest Common Divisor function
'defined in the UDfunctions class module. This need
'an instance in the VBAcallBack class module.
' The determinant of a diagonal matrix. It is defined
' as the product of the elements in its diagonal.
' For our case: 1*2*3=6. (Note that sin(atn(1)*2)=sin(pi/2)=1)
.Create "GCD(1280;240;100;30*cos(0);10*DET({{sin(atn(1)*2); 0; 0}; {0; 2; 0}; {0; 0; 3}}))"
Result = .Eval
End With
End Sub
```
## Working with arrays
VBA expressions can evaluate matrix functions whose arguments are given as arrays/vectors, using a syntax like [Java](https://www.w3schools.com/java/java_arrays.asp). The following expression will calculate, and format to percentage, the internal rate of return (`IRR`) of a cash flow described using a one dimensional array with 5 entries:

`FORMAT(IRR({{-70000;12000;15000;18000;21000}});'Percent')`

However, user-defined array functions need to take care of creating arrays from a string, the `ArrayFromString` method can be used for this purpose.

## Using the code
VBA Expressions is an easy-to-use library, this section shows some examples of how to use the most common properties and methods

$\color{D29922}\textsf{\Large Warning:}$
>[The library](https://extensions.libreoffice.org/en/extensions/show/70059) only works on LibreOffice version 7.5 or higher and, since there is no 1-1 compatibility between VBA and LO Basic, users must be aware of certain changes required to recover some properties functionality. This applies mainly to those properties related to accessing variables, which were converted into functions to overcome the one-parameter limitation imposed by LO Basic when accessing them, as well as to other properties deprecated due to LO Basic's behaviour in handling class modules. An example of this is the `VarValue` property which was split into two procedures: `GetVarValue` and `LetVarValue`. The rest of the syntax is shared between the two implementations.

```
Sub SimpleMathEval()
Dim Evaluator As VBAexpressions
Set Evaluator = New VBAexpressions
With Evaluator
.Create "(((((((((((-123.456-654.321)*1.1)*2.2)*3.3)+4.4)+5.5)+6.6)*7.7)*8.8)+9.9)+10.10)"
If .ReadyToEval Then 'Evaluates only if the expression was successfully parsed.
.Eval
End If
End With
End Sub
Sub LateVariableAssignment()
Dim Evaluator As VBAexpressions
Set Evaluator = New VBAexpressions
With Evaluator
.Create "Pi.e * 5.2Pie.1 + 3.1Pie"
If .ReadyToEval Then
Debug.Print "Variables: "; .CurrentVariables 'Print the list of parsed variables
.Eval ("Pi.e=1; Pie.1=2; Pie=3") 'Late variable assignment
Debug.Print .Expression; " = "; .Result; _
"; for: "; .CurrentVarValues 'Print stored result, expression and values used in evaluation
End If
End With
End Sub
Sub EarlyVariableAssignment()
Dim Evaluator As VBAexpressions
Set Evaluator = New VBAexpressions
With Evaluator
.Create "Pi.e * 5.2Pie.1 + 3.1Pie"
If .ReadyToEval Then
Debug.Print "Variables: "; .CurrentVariables
.VarValue("Pi.e") = 1
.ImplicitVarValue("Pie.1") = "2*Pi.e"
.ImplicitVarValue("Pie") = "Pie.1/3"
.Eval
Debug.Print .Expression; " = "; .Result; _
"; for: "; .CurrentVarValues
End If
End With
End Sub
Sub TrigFunctions()
Dim Evaluator As VBAexpressions
Set Evaluator = New VBAexpressions
With Evaluator
.Create "asin(sin(30))"
If .ReadyToEval Then
.Degrees = True 'Eval in degrees
.Eval
End If
End With
End Sub
Sub StringFunctions()
Dim Evaluator As VBAexpressions
Set Evaluator = New VBAexpressions

With Evaluator
.Create "CONCAT(CHOOSE(1;x;'2nd';'3th';'4th';'5th');'Element';'selected';'/')"
.Eval ("x='1st'")
End With
End Sub
Sub LogicalFunctions()
Dim Evaluator As VBAexpressions
Set Evaluator = New VBAexpressions

With Evaluator
.Create "IFF(x > y & x > 0; x; y)"
.Eval("x=70;y=15") 'This will be evaluated to 70
End With
End Sub
Sub SolveSystemOfLinearEquations()
Dim Evaluator As VBAexpressions

Set Evaluator = New VBAexpressions
With Evaluator
'Create an array of vectors a, b, c, d and e
.Create "SOLVE(ARRAY(a;b;c;d;e);{{'x1';'x2';'x3';'x4';'x5'}};{{100;100;100;100;100}};True)"

'Define coeficient vectors
.VarValue("a") = "{4;-1;0;1;0}"
.VarValue("b") = "{-1;4;-1;0;1}"
.VarValue("c") = "{0;-1;4;-1;0}"
.VarValue("d") = "{1;0;-1;4;-1}"
.VarValue("e") = "{0;1;0;-1;4}"
.Eval 'Evaluates to [x1 = 25; x2 = 35.7142857143; x3 = 42.8571428571; x4 = 35.7142857143; x5 = 25]
End With
End Sub

'@------------------------------------------------------
' Here a list of the new functions and its results
'***********************************ADVANCED MATH FUNCTIONS***************************************************************
''' A={{-2;40};{-1;50};{0;62};{1;58};{2;60}}
''' B={{0;0.1};{0.5;0.45};{1;2.15};{1.5;9.15};{2;40.35};{2.5;180.75}}
''' C={{1;0.01};{2;1};{3;1.15};{4;1.3};{5;1.52};{6;1.84};{7;2.01};{8;2.05};{9;2.3};{10;2.25}}
''' ----------------------------------------------------------------------------
''' | Fitting data model with a 4th degree polynomial |
''' | FIT(A;1;4) : {{62 + 3.6667*x -9.6667*x^2 + 0.3333*x^3 + 1.6667*x^4};{1}} |
''' | |
''' | Exponential Fitting |
''' | FIT(B;2) : {{0.102*e^(2.9963*x)};{0.9998}} |
''' | |
''' | Logarithmic Fitting |
''' | FIT(C;5) : {{0.9521*ln(x)+0.1049};{0.9752}} |
''' ----------------------------------------------------------------------------
'''
''' X={{1;1};{2;2};{3;3};{4;4};{5;1};{6;2};{7;3};{8;4}}
''' Y={{2;4.1;5.8;7.8;5.5;5.2;8.2;11.1}}
''' ------------------------------------------------------------------------------------------
''' | Multivariate Linear Regression with regressors/predictors interaction. |
''' | |
''' | MLR(X;Y;True;'X1:X2') : {{0.8542 + 0.4458*X1 + 0.945*X2 + 0.0792*X1*X2};{0.947;0.9072}} |
''' ------------------------------------------------------------------------------------------
'''
''' ----------------------------------------------------------------
''' | Finding a zero for the given function in the interval -2<=x<=3 |
''' | |
''' | FZERO('2x^2+x-12';-2;3) : x = 2.21221445045296 |
''' ----------------------------------------------------------------
'''
''' a = {1;0;4}; b = {1;1;6}; c = {-3;0;-10}; d = {2;3;4}
''' ------------------------------------------------------------------------------------------------
''' | Using LU decomposition for a given matrix |
''' | |
''' | LUDECOMP(ARRAY(a;b;c)) : |
''' | |
''' | {{-3;0;-10};{-0.333333333333333;1;2.66666666666667};{-0.333333333333333;0;0.666666666666667}} |
''' ------------------------------------------------------------------------------------------------
'''
''' ----------------------------------------------------------------------------------
''' | Using LU decomposition for solve linear equations system |
''' | |
''' | LUSOLVE(ARRAY(a;b;c);{{'x';'y';'z'}};{{2;3;4}};True) : x = -18; y = -9; z = 5 |
''' ----------------------------------------------------------------------------------
'''
''' ---------------------------------------------------------------------------
''' | Using matrix multiplication for solve a linear equations system |
''' | |
''' | MMULT(INVERSE(ARRAY(a;b;c));ARRAY(d)) : {{-18};{-9};{5}} |
''' | MMULT(ARRAY(a;b;c);INVERSE(ARRAY(a;b;c))) : {{1;0;0};{0;1;0};{0;0;1}} |
''' ---------------------------------------------------------------------------
'''
''' A={{2;4};{-5;1},{3;-8}};b={{10;-9.5;12}}
''' --------------------------------------------------------------------
''' | Solving overdetermined system of equations using least squares and |
''' | the QR decomposition |
''' | |
''' | MROUND(LSQRSOLVE(A;b);4) : {{2.6576;-0.1196}} |
''' --------------------------------------------------------------------
'''
'***********************************STATISTICAL FUNCTIONS*******************************************************************************
''' ROUND(NORM(0.05);8) = 0.96012239
''' ROUND(CHISQ(4;15);8) = 0.99773734
''' ROUND(GAUSS(0.05);8) = 0.01993881
''' ROUND(ERF(0.05);8) = 0.05637198
''' ROUND(STUDT(0.8;15);8) = 0.43619794
''' ROUND(ANORM(0.75);8) = 0.31863936
''' ROUND(AGAUSS(0.75);8) = 0.67448975
''' ROUND(AERF(0.95);8) = 1.38590382
''' ROUND(ACHISQ(0.75;15);8) = 11.03653766
''' ROUND(FISHF(5.5;1.5;3);8) = 0.21407698
''' ROUND(ASTUDT(0.05;15);8) = 2.13144955
''' ROUND(AFISHF(0.05;1.5;3);8) = 18.55325631
''' ROUND(iBETA(0.5;1;3);8) = 0.875
''' ROUND(BETAINV(0.5;1;3);8) = 0.20629947
'***********************************FINANTIAL FUNCTIONS*********************************************************************************
''' FORMAT(SYD(10000;5000;5;2);'Currency') = '$1,333.33'
''' FORMAT(SLN(10000;0;5);'Currency') = '$2,000.00'
''' FORMAT(RATE(2*12; -250; 5000; 0; 1);'Percent') = '1.66%'
''' FORMAT(PV(0.075/12; 2*12; 250; 0; 0);'Currency') = '($5,555.61)'
''' FORMAT(PPMT(0.06/52; 20; 4*52; 8000; 0; 0);'Currency') = '($34.81)'
''' FORMAT(PMT(0.075/12; 2*12; 5000; 0; 1);'Currency') = '($223.60)'
''' FORMAT(NPV(0.1;{{-10000;3000;4200;6800}});'Currency') = '$1,188.44'
''' FORMAT(NPER(0.0525/1; -200; 1500);'0.00') = '9.78'
''' FORMAT(MIRR({{-7500;3000;5000;1200;4000}};0.05;0.08);'Percent') = '18.74%'
'''
''' Microsoft example. VBA Expressions use a custom solver to compute IRR
''' FORMAT(IRR({{-70000;12000;15000;18000;21000}});'Percent') = '-2.12%'
''' FORMAT(IRR({{-70000;12000;15000;18000;21000;26000}});'Percent') = '8.66%'
''' FORMAT(IRR({{-70000;12000;15000}};true);'Percent') = '-44.35%' 'Find a solution with negative values for IRR
'''
''' FORMAT(IPMT(0.0525/1; 4; 10*1; 6500);'Currency') = '($256.50)'
''' FORMAT(FV(0.0525/1; 10*1; -100; -6500; 0);'Currency') = '$12,115.19'
''' FORMAT(DDB(10000; 5000; 5; 2);'Currency') = '$1,000.00'
'***********************************DATE AND TIME FUNCTIONS*****************************************************************************
''' YEAR(NOW()) = 2022
''' WEEKDAYNAME(1;true;2) = 'lun.'
''' WEEKDAY(NOW()) = 2
''' TIMEVALUE(NOW()) = '7:53:00 a. m.'
''' TIMESERIAL(x;y;z) = '6:45:50 a. m.' for x = 7; y = -15; z = 50
''' MONTH(NOW()) = 10
''' MONTHNAME(x;y) = 'marzo' for x = 3; y = false
''' MONTH(x) = 10 for x = '10/10/2022 7:53:10 a. m.'
''' MINUTE(x) = 53 for x = '10/10/2022 7:53:12 a. m.'
''' HOUR(x) = 7 for x = '10/10/2022 7:53:15 a. m.'
''' DAY(DATE()) = 10
''' DATEVALUE(DATE()) = '10/10/2022'
''' DATESERIAL(2022;x+2;3y) = '21/12/2022' for x = 10; y = 7
''' DATEPART(x;DATE()) = 2022 for x = 'yyyy'
''' DATEPART(x;DATE()) = 10 for x = 'm'
''' DATEPART(x;DATE()) = 10 for x = 'd'
''' DATEPART(x;DATE()) = 4 for x = 'q'
''' DATEDIFF(x;DATE();DATEADD(x;y;DATE())) = 3 for x = 'yyyy'; y = 3
''' DATEDIFF(x;DATE();DATEADD(x;y;DATE())) = 2 for x = 'q'; y = 2
''' DATEDIFF(x;DATE();DATEADD(x;y;DATE())) = 5 for x = 'm'; y = 5
''' DATEDIFF(x;DATE();DATEADD(x;y;DATE())) = 10 for x = 'd'; y = 10
''' DATEADD(x;y;DATE()) = 10/10/2025 for x = 'yyyy'; y = 3
''' DATEADD(x;y;DATE()) = 10/4/2023 for x = 'q'; y = 2
''' DATEADD(x;y;DATE()) = 10/3/2023 for x = 'm'; y = 5
''' DATEADD(x;y;DATE()) = 20/10/2022 for x = 'd'; y = 10
''' DATE() = '10/10/2022'
'***********************************STRING FUNCTIONS******************************************************************************
''' UCASE(x) = ' THIS STRING ' for x = ' This String '
''' TRIM(x) = 'Capi tal' for x = ' Capi tal '
''' RIGHT(2x+20-5+x;2) = '90' for x = 25
''' RIGHT(2x+20-5+x;2) = '09' for x = 98
''' REPLACE(x;'a';'A';1;2) = 'CApitAl' for x = 'Capital'
''' MID(x;4;3) = 'ion' for x = 'Region'
''' LEN(x) = 6 for x = 'Region'
''' LEFT(2x+20-5+x;2) = '90' for x = 25
''' LEFT(2x+20-5+x;2) = '30' for x = 98
''' LCASE(x) = 'this string' for x = 'This String'
''' LCASE(x) = '98' for x = 98
''' FORMAT(x;'Percent') = '98.10%' for x = 0.981
''' CHR(x) = ';' for x = 59
''' ASC(x) = 82 for x = 'Region'
''' SWITCH(x='Asia';1;x='Africa';2;x='Oceania';3) = 1 for x = 'Asia'
'@------------------------------------------------------
```
## Credits
- [x] **Inquisitive knight**: new logo design. Awesome job!

## Tested
[![Rubberduck](https://user-images.githubusercontent.com/5751684/48656196-a507af80-e9ef-11e8-9c09-1ce3c619c019.png)](https://github.com/rubberduck-vba/Rubberduck/)

## Licence

Copyright: © 2022-2024 [W. García](https://github.com/ws-garcia/).

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see .