Databases
StackOverflow2013
Postsdbo
POParsing a lightweight language in Python
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POParsing a lightweight language in Python
    primarykey
    data
    text
    <p>Say I define a string in Python like the following:</p> <pre><code>my_string = "something{name1, name2, opt1=2, opt2=text}, something_else{name3, opt1=58}" </code></pre> <p>I would like to parse that string in Python in a way that allows me to index the different structures of the language.</p> <p>For example, the output could be a dictionary <code>parsing_result</code> that allows me to index the different elements in a structred manner.</p> <p>For example, the following:</p> <pre><code>parsing_result['names'] </code></pre> <p>would hold a <code>list</code> of strings: <code>['name1', 'name2']</code></p> <p>whereas <code>parsing_result['options']</code> would hold a dictionary so that:</p> <ul> <li><code>parsing_result['something']['options']['opt2']</code> holds the string <code>"text"</code></li> <li><code>parsing_result['something_else']['options']['opt1']</code> holds the string <code>"58"</code></li> </ul> <p>My first question is: How do I approach this problem in Python? Are there any libraries that simplify this task? </p> <p>For a working example, I am not necessarily interested in a solution that parses the exact syntax I defined above (although that would be fantastic), but anything close to it would be great.</p> <h3>Update</h3> <ol> <li><p>It looks like the general right solution is using a parser and a lexer such as <a href="http://www.dabeaz.com/ply/" rel="nofollow noreferrer">ply</a> (thank you @Joran), but the documentation is a bit intimidating. Is there an easier way of getting this done when the syntax is <strong>lightweight</strong>?</p></li> <li><p>I found <a href="https://stackoverflow.com/questions/1648537/how-to-split-a-string-by-commas-positioned-outside-of-parenthesis">this thread</a> where the following regular expression is provided to partition a string around outer commas:</p> <pre><code>r = re.compile(r'(?:[^,(]|\([^)]*\))+') r.findall(s) </code></pre> <p>But this is assuming that the grouping character are <code>()</code> (and not <code>{}</code>). I am trying to adapt this, but it doesn't look easy.</p></li> </ol>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USAmelio Vazquez-Reina
    plurals
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POParsing a lightweight language in Python
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POParsing a lightweight language in Python
      1. USJosh
      1. VTFavorite
    3. VO
      singulars
      1. POParsing a lightweight language in Python
      1. This table or related slice is empty.
      1. VTUpMod
    1. COyou need a parser and a lexer ... try ply for python (thats the one i usually use...) ... its a fair bit of work defining a language
      singulars
      1. POParsing a lightweight language in Python
      1. USJoran Beasley
    2. COIf the language is sufficiently lightweight, you can use regular expressions. The language implied by your example is such a language, I believe.
      singulars
      1. POParsing a lightweight language in Python
      1. USRobᵩ
    3. COIf the sentences in your language are also sentences in Python, you can use `ast.parse()`.
      singulars
      1. POParsing a lightweight language in Python
      1. USRobᵩ
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload