php - Parsing Preformatted Formula to Array Recursively -

-

i trying create formula parser , stuck on how recursively convert code array of expressions. take following formula example:

$formula = "     @var[a, 3];     @if[ (a <= 3) & (a = 3) ]:         @var[a, + 4];         @if[ > 5 ]:             @use[a];         @endif     @elseif[ > 4 ]:         @var[a, 2];     @else:         @var[a, 5];     @endif     @var[a,5];     @use[a]; ";

should output:

{     "0": "var[a, 3];",     "if[ (a <= 3) & (a = 3) ]:": {         "0": "var[a, + 4];",         "1": "endif",         "if[ > 5 ]:": [             "use[a];"         ]     },     "elseif[ > 4 ]:": [         "var[a, 2];"     ],     "else:": [         "var[a, 5];"     ],     "1": "endif",     "2": "var[a,5];",     "3": "use[a];", }

so can iterate through each item , evaluate each expression.

i have following code, doesn't output expected format.

<?php  $formula = "     @var[a, 3];     @if[ (a <= 3) & (a = 3) ]:         @var[a, + 4];         @if[ > 5 ]:             @use[a];         @endif     @elseif[ > 4 ]:         @var[a, 2];     @else:         @var[a, 5];     @endif     @var[a,5];     @use[a]; ";  $formulas = explode( "@", $formula ); $result = parse( $formulas );  echo json_encode( $result ); function parse( $lines  ){     $exec_tree = array();     foreach( $lines $i => $block ){         unset( $lines[$i] );         $block = trim( str_replace( array(" ") , "" , preg_replace('/\s\s+/', ' ', $block) ) );         if( trim( $block ) != "" ){              // match variable assignments             if( preg_match('/var\[(.*)\]\;?/', $block ) ){                 $exec_tree[] = $block;                         }                // match use statements             if( preg_match('/use\[(.*)\]\;?/', $block ) ){                 $exec_tree[] = $block;             }                   // match ifs             if( preg_match('/^if\[(.*)\]\:/', $block ) ){                 $exec_tree[$block] = parse( $lines );             }                     // match elseifs             if( preg_match('/^elseif\[(.*)\]\:/', $block ) ){                 $exec_tree[$block] = parse( $lines );             }                 // match elses             if( preg_match('/^else:/', $block ) ){                 $exec_tree[$block] = parse( $lines );             }                   // match endifs             if( preg_match('/^endif/', $block ) ){                 break;             }         }     }     return $exec_tree; }

the code recursive in nature, think missing termination of recursion. it's supposed end on endif keywords. can point me right direction appreciated.

this output now: (json formatted)

[ "var[a,3];", [     "if[(a<=3)&(a=3)]:",     [         "var[a,a+4];",         [             "if[a>5]:",             [                 "use[a];"             ]         ],         "use[a];"     ] ], "var[a,a+4];", [     "if[a>5]:",     [         "use[a];"     ] ], "use[a];"

]

thanks,

jan

admittedly not entirely clean solution, working , easy refactor:

<?php  $formula = "     @var[a, 3];     @if[ (a <= 3) & (a = 3) ]:         @var[a, + 4];         @if[ > 5 ]:             @use[a];         @endif     @elseif[ > 4 ]:         @var[a, 2];     @else:         @var[a, 5];     @endif     @var[a,5];     @use[a]; ";  $formulas = explode( "@", $formula ); $rec = false; $result   = parse( $formulas, $rec );  echo json_encode( $result, json_pretty_print );  function parse( &$lines, &$rec ) {     $exec_tree = array();     while ( (bool) $lines === true ) {         $block = array_shift( $lines );          $block = trim( str_replace( array( " " ), "", preg_replace( '/\s\s+/', ' ', $block ) ) );         if ( trim( $block ) != "" ) {              // match variable assignments             if ( preg_match( '/var\[(.*)\]\;?/', $block ) ) {                 $exec_tree[] = $block;             } elseif ( preg_match( '/use\[(.*)\]\;?/', $block ) ) {                 $exec_tree[] = $block;             } elseif ( preg_match( '/^if\[(.*)\]\:/', $block ) ) {                 $rec = true;                 $exec_tree[ $block ] = parse( $lines, $rec );             } elseif ( preg_match( '/^elseif\[(.*)\]\:/', $block ) ) {                 $rec = !$rec;                 if ( $rec === false ) {                     array_unshift( $lines, $block );                     break;                 } else {                     $exec_tree[ $block ] = parse( $lines, $rec );                 }             } elseif ( preg_match( '/^else:/', $block ) ) {                 $rec = !$rec;                 if ( $rec === false ) {                     array_unshift( $lines, $block );                     break;                 } else {                     $exec_tree[ $block ] = parse( $lines, $rec );                 }             } elseif ( preg_match( '/^endif/', $block ) ) {                 $rec = !$rec;                 if ( $rec === false ) {                     array_unshift( $lines, $block );                     break;                 } else {                     $exec_tree[] = $block;                 }             }         }     }      return $exec_tree; }

returns

{     "0": "var[a,3];",     "if[(a<=3)&(a=3)]:": {         "0": "var[a,a+4];",         "if[a>5]:": [             "use[a];"         ],         "1": "endif"     },     "elseif[a>4]:": [         "var[a,2];"     ],     "else:": [         "var[a,5];"     ],     "1": "endif",     "2": "var[a,5];",     "3": "use[a];" }

the trick somehow keep track of whether or not you're in block , break out on else,elseif , endif, though still appending values end result.


Comments

Post a Comment

Popular posts from this blog

javascript - Slick Slider width recalculation -

-
i'm trying add slide in panel on slick container css. carousel works except new width not being calculated when space has been added. recalibrate once advance next slide i'd happen each time panel opened or closed. i've tried adding both margin , padding, neither makes difference. ideas? https://jsfiddle.net/mhigley/dpf7mlpl/ html: <button type="button" id="button"><i class="fa fa-arrow-right"></i></button> <aside> <h2>slide in panel</h2> <ol> <li>list item</li> <li>list item</li> <li>list item</li> <li>list item</li> <li>list item</li> </ol> </aside> <main role="main"> <div class="sections"> <section> <article> <h2>first slide</h2> <p>lorem ipsum d...
Read more

jsf - PrimeFaces Datatable - What is f:facet actually doing? -

-
looking through primefaces code in app noticed following line: <f:facet name="header">#{trainsearch.traincount} trains</f:facet> it looks overriding header, makes sense, can explain me in little more detail? what happening line of code? complete code listed below: <p:datatable id = "results" value = "#{trainsearch.trains}" var = "train" rendered="#{not empty trainsearch.trains}" styleclass = "train-search-table horizontal-border"> <f:facet name="header">#{trainsearch.traincount} trains</f:facet> <p:column headertext = "train id"> <p:panelgrid columns="1" styleclass = "train-id-grid" layout = "grid"> <h:outputtext styleclass = "train-id-label" value="#{train.traini}"/> <h:outputtex...
Read more

angular2 services - Angular 2 RC 4 Http post not firing -

-
i trying fire post request app , it's not working, tried multiple ways. don't see request being fired under network tab in chrome. not sure problem is, appreciated. import { injectable } '@angular/core'; import { http, headers } '@angular/http'; @injectable() export class userservice{ private _url="users"; constructor(private _http: http){ } checkifusernameexists(username){ return this._http.get(this._url+"/"+username) .map(response => response.json()) } createuser(user){ let headers = new headers(); headers.append('content-type', 'application/json') console.log(json.stringify(user)); return this._http.post(this._url, json.stringify(user),{headers: headers}) .map(response => response.json()) } } first need capture error , solve error: this._http.post(this._url, json.stringify(user),{headers: headers}) .subscribe( ...
Read more