https://github.com/anupam-io/strange-if-else

A simple bison based parser to detect and solve a strange if-else sequence.
https://github.com/anupam-io/strange-if-else

bison compiler flex grammar lex lexical-analyzer yacc

Last synced: 10 days ago
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A simple bison based parser to detect and solve a strange if-else sequence.

• Host: GitHub
• URL: https://github.com/anupam-io/strange-if-else
• Owner: anupam-io
• Created: 2021-02-05T10:16:43.000Z (almost 4 years ago)
• Default Branch: master
• Last Pushed: 2021-02-05T18:47:28.000Z (almost 4 years ago)
• Last Synced: 2024-09-11T12:59:06.905Z (about 2 months ago)
• Topics: bison, compiler, flex, grammar, lex, lexical-analyzer, yacc
• Language: Lex
• Homepage:
• Size: 1.95 KB
• Stars: 1
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# strange `if-else` parser using Flex & Bison

This is a simple parser which can parse expressions in a strange way. The syntax for this language is very similar to `if-else` of C++. Inside curly braces or round braces, you can enter numbers or similar expressions and it will evaluate the final result.

## Tokens used

```

digit       [0-9]+

if          "if"

else        "else"

cleft       "{"

cright      "}"

rleft       "("

rright      ")"

```

## Grammar used

 - rL = round left = `(`

 - cL = curly left =  `{`

```

prog:

	prog atom

|	prog SEMICOLON

|

atom:

	IF rL atom rR cL atom cR ELSE cL atom cR

|	IF rL atom rR cL atom cR

|	DIGIT

```

## Sample inputs

```

if(1){33}

else{55};

```

```

if(1){

    if(1){33}

    else{55}

}

else{

    if(1){33}

    else{55}

};

```

## How to run?

 - `make`

 - Enter inputs as mentioned above.