Consistent Looping in ColdFusion

I've said this before, but I hate how inconsistent looping is in ColdFusion. And to make matters worse, ColdFusion 9 script syntax doesn't support looping over arrays using for...in statements. Why not?

I decided to try to ease my pain by creating a custom tag to loop over data in a consistent way. Here's what I came up with.

Usage

<cfimport prefix="for" taglib="/com/tags" />

<for:each key="key" in="#data#" value="value" index="i">
     ... stuff ...
</for:each>

Examples

<cfimport prefix="for" taglib="/com/tags" />

<cfoutput>
Array

<cfset people = [] />
<cfset people[1] = "LeBron James" />
<cfset people[2] = "Dwyane Wade" />
<cfset people[3] = "Kobe Bryant" />

<for:each in="#people#">
      Hello, my name is #it#
</for:each>

Struct

<cfset people = {} />
<cfset people["LeBronJames"] = "LeBron James" />
<cfset people["DwyaneWade"] = "Dwyane Wade" />
<cfset people["KobeBryant"] = "Kobe Bryant" />

<for:each in="#people#" value="name">
      Hello, my name is #name#
</for:each>

List

<cfset people = "LeBron James,Dwyane Wade,Kobe Bryant" /> 

<for:each in="#people#">
      Hello, my name is #it#
</for:each>

Query

<cfset people = queryNew("firstName,lastName") />

<cfset queryAddRow(people) />
<cfset querySetCell(people, "firstName", "LeBron") />
<cfset querySetCell(people, "lastName", "James") />

<cfset queryAddRow(people) />
<cfset querySetCell(people, "firstName", "Dwyane") />
<cfset querySetCell(people, "lastName", "Wade") />

<cfset queryAddRow(people) />
<cfset querySetCell(people, "firstName", "Kobe") />
<cfset querySetCell(people, "lastName", "Bryant") /> 

<for:each in="#people#" value="person">
      Hello, my name is #person.firstName# #person.lastName#
</for:each>

Nested Array

<cfset people = [] />
<cfset people[1] = {firstName="LeBron", lastName="James"} />
<cfset people[2] = {firstName="Dwyane", lastName="Wade"} />
<cfset people[3] = {firstName="Kobe", lastName="Bryant"} />

<for:each in="#people#" value="person">
      Hello, my name is #person.firstName# #person.lastName#
</for:each>

Nested Struct

<cfset people = {} />

<cfset people["LeBronJames"] = {firstName="LeBron", lastName="James"} />
<cfset people["DwyaneWade"] = {firstName="Dwyane", lastName="Wade"} />
<cfset people["KobeBryant"] = {firstName="Kobe", lastName="Bryant"} />
 
<for:each in="#people#" value="person">
      Hello, my name is #person.firstName# #person.lastName#
</for:each>
</cfoutput>

And here's the code
/com/tags/for/each.cfm

<cfif thisTag.executionMode eq "start">

      <cfparam name="attributes.value" default="it" />
      <cfparam name="attributes.in" default="" />
      <cfparam name="attributes.start" default="1" />
      <cfparam name="attributes.delimeter" default="," />
 
      <cfset attributes.type = getType(attributes.in) />
      <cfset attributes.length = getLength(attributes.in, attributes.type, attributes.delimeter) />

      <cfif not structKeyExists(attributes, "end")>
            <cfset attributes.end = attributes.length />
      </cfif>

      <cfif attributes.length>       
            <cfset processLoop(attributes) />
      <cfelse>         
            <cfexit method="exittag" />        
      </cfif>

      <cfset content = [] />

<cfelse>

      <cfset arrayAppend(content, thisTag.generatedContent) />

      <cfset thisTag.generatedContent = "" />

      <cfset attributes.start++ />

      <cfif attributes.start lte attributes.end>
            <cfset processLoop(attributes) />
            <cfexit method="loop" />
      </cfif>

      <cfoutput>
            #arrayToList(content, "")#
      </cfoutput>

</cfif>

<cffunction name="processLoop" access="private" output="false" returntype="void">
      <cfargument name="attributes" required="true" type="struct" />   

      <cfif structKeyExists(attributes, "index")>
            <cfset caller[attributes.index] = attributes.start />
      </cfif>

      <cfif structKeyExists(attributes, "key")>
            <cfset caller[attributes.key] = getKey(attributes.in, attributes.type, attributes.delimeter, attributes.start) />
      </cfif>

      <cfif structKeyExists(attributes, "value")>
            <cfset caller[attributes.value] = getValue(attributes.in, attributes.type, attributes.delimeter, attributes.start) />
      </cfif>

</cffunction>

<cffunction name="getType" access="private" output="false" returntype="string">
      <cfargument name="data" required="true" type="any" />

      <cfif isArray(arguments.data)>
            <cfreturn "array" />
      <cfelseif isStruct(arguments.data)>
            <cfreturn "struct" />
      <cfelseif isQuery(arguments.data)>
            <cfreturn "query" />
      <cfelse>
            <cfreturn "string" />
      </cfif>

</cffunction>

<cffunction name="getLength" access="private" output="false" returntype="numeric">
      <cfargument name="data" required="true" type="any" />
      <cfargument name="type" required="true" type="string" />
      <cfargument name="delimeter" required="true" type="string" />

      <cfswitch expression="#arguments.type#">

            <cfcase value="array">
                  <cfreturn arrayLen(arguments.data) />
            </cfcase>

            <cfcase value="struct">
                  <cfreturn structCount(arguments.data) />
            </cfcase>

            <cfcase value="query">
                  <cfreturn arguments.data.recordCount />
            </cfcase>

            <cfcase value="string">
                  <cfreturn listLen(arguments.data, arguments.delimeter) />
            </cfcase>

      </cfswitch>

</cffunction>

<cffunction name="getKey" access="private" output="false" returntype="string">
      <cfargument name="data" required="true" type="any" />
      <cfargument name="type" required="true" type="string" />
      <cfargument name="delimeter" required="true" type="string" />
      <cfargument name="index" required="true" type="numeric" />
     
      <cfset var result = "" />

      <cfset var i = "" />

      <cfswitch expression="#arguments.type#">

            <cfcase value="array">
                  <cfset result = arguments.index />
            </cfcase>

            <cfcase value="struct">
                  <cfset result = listGetAt(listSort(structKeyList(arguments.data), "text"), arguments.index) />
            </cfcase>

            <cfcase value="query">
                  <cfset result = arguments.index />
            </cfcase>

            <cfcase value="string">
                  <cfset result = listGetAt(arguments.data, arguments.index, arguments.delimeter) />
            </cfcase>

      </cfswitch>

      <cfreturn result />

</cffunction>

<cffunction name="getValue" access="private" output="false" returntype="any">
      <cfargument name="data" required="true" type="any" />
      <cfargument name="type" required="true" type="string" />
      <cfargument name="delimeter" required="true" type="string" />
      <cfargument name="index" required="true" type="numeric" />

      <cfset var result = "" />
      <cfset var i = "" />

      <cfswitch expression="#arguments.type#">

            <cfcase value="array">
                  <cfset result = arguments.data[arguments.index] />
            </cfcase>

            <cfcase value="struct">
                  <cfset result = arguments.data[listGetAt(listSort(structKeyList(arguments.data), "text"), arguments.index)] />
            </cfcase>

            <cfcase value="query">
                  <cfset result = {} />
                  <cfloop list="#arguments.data.columnList#" index="i">
                        <cfset result[i] = arguments.data[i][arguments.index] />
                  </cfloop>
            </cfcase>

            <cfcase value="string">
                  <cfset result = listGetAt(arguments.data, arguments.index, arguments.delimeter) />
            </cfcase>

      </cfswitch>

      <cfreturn result />

</cffunction>

It's been quite a while since I've used custom tags, so the code could probably be better, but it seems to do the job.