On Mon, Mar 14, 2011 at 2:17 PM, Daniel Solano Gomez
<[email protected]> wrote:
> On Mon Mar 14 13:02 2011, shuaybi2 shuaybi2 wrote:
>> I have a string such as:
>>
>> "select * from account where acctId = _ACCT-ID_ and acctTyp = _ACCT-TYP_"
>>
>> I have a map such as:
>>
>> {:_ACCT-ID_ 9876 :_ACCT-TYP "B"}
>>
>> I want to write a clojure function that will take the string and map as a
>> parameter and return me the string with all values from the map substituted.
>>
>> Output:
>>
>> select * from account where acctId = 9876 and acctTyp = 'B'
>>
>> Thanks for your help.
>
> Something like the following does the trick:
>
> (defn substitute-mappings
> [string mappings]
> (let [substitute-mapping
> (fn [string mapping]
> (let [pattern (java.util.regex.Pattern/quote (name (key mapping)))
> pattern (re-pattern pattern)
> matcher (re-matcher pattern string)
> replacement (java.util.regex.Matcher/quoteReplacement (str
> (val mapping)))]
> (.replaceAll matcher replacement)))]
> (reduce substitute-mapping string (seq mappings))))
>
> It uses reduce with an local function so that the string gets its
> replacements one at a time. Actually doing the replacement uses Java's
> regular expressions.
>
> Just a few notes about the above:
>
> 1. quote and quoteReplacement to take care of any special characters
> that may otherwise muck up replacement process
> 2. The name function is used to convert a keyword to a string without
> the initial colon.
> 3. For integers and the like, I use the str function to coerce them into
> a string that can be used as a replacement pattern. So, you'd want
> to make sure this works correctly with any data types you want to
> use.
Do we have a str function that will prevent the use of {:_ACCT-ID_
"9876; delete * from account;"}? ;)
Or are those maps only ever going to be visible to the application's internals?
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