1. A method comprising: outputting, by a computing device and for display at a presence-sensitive display, a graphical keyboard comprising a group of keys, wherein each key in the group of keys is associated with a respective, different region of the presence-sensitive display; receiving, at the computing device, an indication of a gesture to select a sequence of keys that are each included in the group of keys of the graphical keyboard; determining, by the computing device, that the selected sequence of keys corresponds to a character string that is identifiable by at least one format source, wherein the format source is associated with a syntax; determining, by the computing device and based at least in part on the syntax, that at least one separator character is associated with the character string; and in response to determining that the at least one separator character is associated with the character string, outputting, by the computing device and for display at the presence-sensitive display, the character string and the at least one separator character at a location proximal to the character string.