8. A non-transitory computer-readable medium containing a program comprising a document management system (DMS) and which, when executed, performs an operation of keeping result documents, transformed from source documents, current when the source documents are modified, the operation comprising: receiving a source document by the DMS; fragmenting the source document into a constituent set of document fragments; and applying the document transformation to the set of document fragments to generate a set of result fragments; generating a fragment link table based on a set of links established between: (i) each document fragment of the constituent set of document fragments and (ii) a corresponding result fragment of the set of result fragments; wherein the document transformation specifies a set of rules to transform the source document into a result document; subsequent to generating the fragment link table, receiving a request to apply the document transformation to the source document; responsive to the request, identifying the constituent set of document fragments generated from the source document, wherein each source fragment is associated with one or more rules of the set of rules for transforming the source document into the result document, wherein each of the constituent set of document fragments is stored in the DMS as a distinct document used to build the source document; determining that one of the document fragments, from the set of document fragments generated from the source document, has been modified since a last time the document transformation was applied to the source document, including: (i) evaluating a timestamp associated with the constituent set of document fragments and (ii) analyzing a transformation status flag associated with the constituent set of document fragments; upon detecting occurrence of an event for performing a partial transformation, applying the one or more rules of the set of rules associated with the modified document fragment and by the DMS when executed by one or more computer processors, in order to generate a transformed result fragment, wherein the event is defined by the one or more rules; storing the transformed result fragment in a result fragment cache; assembling the transformed result fragment and a set of unmodified result fragments in order to form the result document without transforming the entirety of the source document having the modified document fragment; and returning the result document in response to the request; wherein the DMS is configured to, upon detecting occurrence of an event for performing a full transformation, transform the entirety of the source document having the modified document fragment, into the result document and without generating any transformed result fragments, wherein the event for performing the full transformation comprises, in respective instances: (i) a date last transformed; (ii) a percentage of modified fragments; and (iii) a user specifying to perform the full transformation; wherein the DMS is operatively connected to a client application, the client application comprising a plurality of components including a DMS plug-in and a transformation display tool, wherein the DMS plug-in permits the client application to interact with the DMS, wherein the transformation display tool is configured to render the result document; wherein the source document is an Extensible Markup Language (XML) document, wherein the document transformation is an Extensible Stylesheet Language Transformations (XSLT) transformation, wherein each of the constituent set of document fragments is a partial source tree of the XML document, wherein the XSLT transformation is used to generate a Hypertext Markup Language (HTML) document from the XML document.
8. A non-transitory computer-readable medium containing a program comprising a document management system (DMS) and which, when executed, performs an operation of keeping result documents, transformed from source documents, current when the source documents are modified, the operation comprising: receiving a source document by the DMS; fragmenting the source document into a constituent set of document fragments; and applying the document transformation to the set of document fragments to generate a set of result fragments; generating a fragment link table based on a set of links established between: (i) each document fragment of the constituent set of document fragments and (ii) a corresponding result fragment of the set of result fragments; wherein the document transformation specifies a set of rules to transform the source document into a result document; subsequent to generating the fragment link table, receiving a request to apply the document transformation to the source document; responsive to the request, identifying the constituent set of document fragments generated from the source document, wherein each source fragment is associated with one or more rules of the set of rules for transforming the source document into the result document, wherein each of the constituent set of document fragments is stored in the DMS as a distinct document used to build the source document; determining that one of the document fragments, from the set of document fragments generated from the source document, has been modified since a last time the document transformation was applied to the source document, including: (i) evaluating a timestamp associated with the constituent set of document fragments and (ii) analyzing a transformation status flag associated with the constituent set of document fragments; upon detecting occurrence of an event for performing a partial transformation, applying the one or more rules of the set of rules associated with the modified document fragment and by the DMS when executed by one or more computer processors, in order to generate a transformed result fragment, wherein the event is defined by the one or more rules; storing the transformed result fragment in a result fragment cache; assembling the transformed result fragment and a set of unmodified result fragments in order to form the result document without transforming the entirety of the source document having the modified document fragment; and returning the result document in response to the request; wherein the DMS is configured to, upon detecting occurrence of an event for performing a full transformation, transform the entirety of the source document having the modified document fragment, into the result document and without generating any transformed result fragments, wherein the event for performing the full transformation comprises, in respective instances: (i) a date last transformed; (ii) a percentage of modified fragments; and (iii) a user specifying to perform the full transformation; wherein the DMS is operatively connected to a client application, the client application comprising a plurality of components including a DMS plug-in and a transformation display tool, wherein the DMS plug-in permits the client application to interact with the DMS, wherein the transformation display tool is configured to render the result document; wherein the source document is an Extensible Markup Language (XML) document, wherein the document transformation is an Extensible Stylesheet Language Transformations (XSLT) transformation, wherein each of the constituent set of document fragments is a partial source tree of the XML document, wherein the XSLT transformation is used to generate a Hypertext Markup Language (HTML) document from the XML document. 11. The non-transitory computer-readable medium of claim 8 , wherein the operation further comprises: establishing a set of links between each respective document fragment and corresponding result fragment.