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https://github.com/stefanhaustein/expressionparser
Simple configurable Java parser for mathematical expressions
https://github.com/stefanhaustein/expressionparser
Last synced: 2 months ago
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Simple configurable Java parser for mathematical expressions
- Host: GitHub
- URL: https://github.com/stefanhaustein/expressionparser
- Owner: stefanhaustein
- License: apache-2.0
- Created: 2016-03-13T02:22:33.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2024-06-05T23:01:20.000Z (7 months ago)
- Last Synced: 2024-11-01T04:51:46.593Z (2 months ago)
- Language: Java
- Homepage:
- Size: 385 KB
- Stars: 26
- Watchers: 4
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# ExpressionParser
A simple configurable Java [parser](core/src/main/java/org/kobjects/expressionparser/ExpressionParser.java) for mathematical expressions.
For a kotlin version, please refer to https://github.com/kobjects/parsek
## Examples and Demos
### Immediate evaluation
[Calculator.java](demo/calculator/src/main/java/org/kobjects/expressionparser/demo/calculator/Calculator.java) in the demo package contains a simple self-contained use case directly interpreting the input.
The parser configuration supports simple mathematical expressions, and the processor just evaluates them immediately, without constructing an intermediate tree representation.
```
Expression? 5+2*-2^3^2
Result: -1019.0
```
[SetDemo.java](demo/sets/src/main/java/org/kobjects/expressionparser/demo/sets/SetDemo.java) is similar to the calculator demo,
but illustrates the flexibility of the expression parser with a slightly more "atypical" expression language.
Example output from [SetDemo.java]:
```
Operators: ∩ ∪ ∖
Expression? | {A, B, B, C}|
Result: 3
Expression? {1, 2, 3} ∪ {3, 4, 5}
Result: {1.0, 2.0, 3.0, 4.0, 5.0}
Expression? {1, 2} ∩ {2, 3}
Result: {2.0}
Expression? | {A, B, C} \ {A, X, Y} |
Result: 2
```
Try it:
```
git clone https://github.com/stefanhaustein/expressionparser.git
cd expressionparser
gradle :demo:set:run
```
### Tree building
[TreeBuilder.java](demo/cas/src/main/java/org/kobjects/expressionparser/demo/cas/TreeBuilder.java) shows how to builds a tree from the input (using a [node factory](demo/cas/src/main/java/org/kobjects/expressionparser/demo/cas/tree/NodeFactory.java). The corresponding [demo app](demo/cas/src/main/java/org/kobjects/expressionparser/demo/cas/) is able to do simplifications and to compute the symbolic derivative. An extended tokenizer translates superscript digits.
```
Input? derive(1/x, x)
Parsed: derive(1/x, x)
⎛1 ⎞
⎝x ⎠
(-derive(x, x)) ⎪
Equals: ─────────────── ⎪ Reciprocal rule
x² ⎪
(-1)
Equals: ────
x²
-1
Equals: ──
x²
Flat: -1/x²
```
Try it:
```
git clone https://github.com/stefanhaustein/expressionparser.git
cd expressionparser
gradle :demo:cas:run
```
### Integration with a "main" parser
The [BASIC demo parser](demo/basic/src/main/java/org/kobjects/expressionparser/demo/basic/Parser.java) is able to parse 70's BASIC programs. The rest of the [BASIC demo directory](src/main/java/org/kobjects/expressionparser/demo/basic/) contains some code to run them.
```
**** EXPRESSION PARSER BASIC DEMO V1 ****
251392K SYSTEM 252056464 BASIC BYTES FREE
READY.
print "Hello World"
Hello World
READY.
10 print "Hello World"
list
10 PRINT "Hello World"
READY.
run
Hello World
load "http://www.vintage-basic.net/bcg/superstartrek.bas"
run
,------*------,
,------------- '--- ------'
'-------- --' / /
,---' '-------/ /--,
'----------------'
THE USS ENTERPRISE --- NCC-1701
YOUR ORDERS ARE AS FOLLOWS:
DESTROY THE 14 KLINGON WARSHIPS WHICH HAVE INVADED
THE GALAXY BEFORE THEY CAN ATTACK FEDERATION HEADQUARTERS
ON STARDATE 2328 THIS GIVES YOU 28 DAYS. THERE ARE
4 STARBASES IN THE GALAXY FOR RESUPPLYING YOUR SHIP
YOUR MISSION BEGINS WITH YOUR STARSHIP LOCATED
IN THE GALACTIC QUADRANT, 'ALTAIR I'.
COMBAT AREA CONDITION RED
SHIELDS DANGEROUSLY LOW
---------------------------------
STARDATE 2300
* CONDITION *RED*
+K+ QUADRANT 6,1
SECTOR 8,2
PHOTON TORPEDOES 10
* TOTAL ENERGY 3000
SHIELDS 0
<*> KLINGONS REMAINING14
---------------------------------
COMMAND?
```
Try it:
```
git clone https://github.com/stefanhaustein/expressionparser.git
cd expressionparser
gradle :demo:basic:run
```
## Gradle Build Integration
Jitpack for the win!
Step 1: Add jitpack to your root build.gradle at the end of repositories:
allprojects {
repositories {
...
maven { url 'https://jitpack.io' }
}
}
Step 2: Add the expressionparser dependency
dependencies {
compile 'com.github.stefanhaustein.expressionparser:core:v1.0.0'
}