[Code] Parsing arithmetic formulas

fredo6

Here are a set of standalone methods that can parse a string as an arithmetic value or formula for Integers, Floats and Lengths.

They are actually derived from some work I have done in LibFredo6 (in module Traductor).

I enclosed the methods in a module called ArithmeString, which you can of course change if you enclose some of this code in your script.

string_to_integer--> parse a string as an integer
string_to_integer_formula--> parse a string as a formula evaluating as an integer
string_to_float--> parse a string as a float
string_to_float_formula--> parse a string as a formula evaluating as a float
string_to_length--> parse a string as a length
string_to_length_formula--> parse a string as a formula evaluating as a length

Note that all methods accepts the "." or the "," as valid decimal delimiter, regardless of the underlying locale of the operating system and SU version language.

All the formula methods accepts parentheses to manage more complex calculations.
For lengths, there is a logical order to respect for specifying units and numbers (ex: 2cm * 4, NOT 4 * 2cm)

The attached file contains the methods with some additional comments
Arithmetic parsing.rb

Fredo

TIG

Thanks Fredo
I knew someone must have done more on it.
The nearest I have is in my roof tools where you can specify a slope in degrees [25.0], a ridge height [^3.5] or a pitch [2:3]. The tool then spots which type it is and runs the appropriate method, e.g. using a Math.tan() on the A:B version...

fredo6

@tig said:

Thanks Fredo
I knew someone must have done more on it.
The nearest I have is in my roof tools where you can specify a slope in degrees [25.0], a ridge height [^3.5] or a pitch [2:3]. The tool then spots which type it is and runs the appropriate method, e.g. using a Math.tan() on the A:B version...

TIG,

Thanks. I wonder why this is not embedded in Ruby (or maybe it is in a package that is not included in the Ruby distribution of Sketchup). My real problem is with the length. I have real difficulty with the architectural notation!

Fredo

Dan Rathbun

Some related links:

Perl 5 module Math::String

Java class MathString

recognizing Math functions in Strings with Regex

Dan Rathbun

@unknownuser said:

I wonder why this is not embedded in Ruby (or maybe it is in a package that is not included in the Ruby distribution of Sketchup).

I checked the extended Ruby libraries, but nothing seems to be like this (or the Perl module or Java class, MathString.)

I also did a search at RubyForge to see if anyone else had a similar project, but did not find anything.

@unknownuser said:

My real problem is with the length. I have real difficulty with the architectural notation!

The Sketchup API already extended the Ruby base String class with a .to_l method.
Can you use that method call within your module's length converter methods?

I also wonder if this module would be easier to use as a custom String subclass?

ktkoh

I used this code in my joint tools and found it very useful as the user could enter equation if they do not know the actual value. However I could not make it work if the user entered the " for inches as sketch-up does.

Keith