BACKGROUND [1] In online search, users often have a need that can be met through a number of different web pages. The information or commercial need of the user can often be described by a concept or a set of concepts with a set of constraints. However, most search engines require users to try finding information by knowing what phrases might frequently appear on the page. [2] Similarly, in online advertising, advertisers have to provide long lists of keywords or phrases that they hope the user would type as part of the query when searching for their products. Even with the advertisers' efforts, some keywords are unique and hard to use for ad targeting. For example, a product SKU can be forgotten when generating the keyword list. Further, the product SKU may be hard to use for searching. SUMMARY [3] The present invention is defined by the claims below. Embodiments of the present invention solve at least the above problems by providing media and methods for executing a keyword expression language to match keyword expression language syntax to search queries and ads, generating keywords from a pattern using the keyword expression language, and generating keywords from a token using the keyword expression language. [4] A keyword expression language greatly simplifies the way advertisers target users. The keyword expression language provides users with a simpler way to search using more general concepts. The keyword expression language allows an advertiser to submit characters to a publisher rather than submit complete lists of keywords. The publisher can match the characters or words that come from the characters to search queries and ads. The publisher can also generate keywords from the characters, and the keywords relate to ads provided by the advertiser. The submission of the characters reduces the effort that the advertiser spends on keyword generation. Rather than the advertiser generating the keywords, the publisher uses the characters or generates the keywords. The keywords are generated through a permutation of the characters. Within the keyword expression language, the characters may be expressed as keyword expression language syntax or token syntax. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [5] Illustrative embodiments of the present invention are described in detail below with reference to the attached drawing figures, which are incorporated by reference herein and wherein: [6] FIG. 1 is a block diagram of an exemplary operating environment implementing an embodiment of the present invention; [7] FIG. 2A is an illustration of an exemplary syntax and results when implementing the keyword expression language in an embodiment of the present invention; [8] FIG. 2B is an illustration of exemplary tokens and results when implementing the keyword expression language in an embodiment of the present invention; FIG. 3 is a flowchart of an exemplary process for executing a keyword expression language to generate keywords for a search when practicing an embodiment of the present invention; [10] FIG. 4 is a flowchart of an exemplary process for generating keywords from a pattern using a keyword expression language when practicing an embodiment of the present invention; [11] FIG. 5 is a flowchart of another exemplary process for generating keywords from a token using a keyword expression language when practicing an embodiment of the present invention; and [12] FIG. 6 is a flowchart of an exemplary process for executing a keyword expression language to match keyword expression language syntax to search queries and [13] when practicing an embodiment of the present invention. [14] DETAILED DESCRIPTION [13] Embodiments of the present invention provide media and methods for executing a keyword expression language to match keyword expression language syntax to search queries and ads, generating keywords from a pattern using the keyword expression language, and generating keywords from a token using the keyword expression language. [14] Many different arrangements of the various components depicted, as well as components not shown, are possible without departing from the spirit and scope of the present invention. Embodiments of the present invention will be described with the intent to be illustrative rather than restrictive. Alternative embodiments will become apparent to those skilled in the art. A skilled artisan may develop alternative means of implementing improvements without departing from the scope of the present invention. [15] As one skilled in the art will appreciate, embodiments of the present invention may be embodied as, among other things: a method, system, or computer- program product. Accordingly, the embodiments may take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware. In one embodiment, the present invention takes the form of a computer- program product that includes computer-useable instructions embodied on one or more computer-readable media. [16] Computer-readable media include both volatile and nonvolatile media, removable and nonremovable media, and contemplates media readable by a database, a switch, and various other network devices. Network switches, routers, and related components are conventional in nature, as are means of communicating with the same. By way of example, and not limitation, computer-readable media comprise computer- storage media and communications media. [17] Computer-storage media, or machine-readable media, include media implemented in any method or technology for storing information. Examples of stored information include computer-useable instructions, data structures, program modules, and other data representations. Computer-storage media include, but are not limited to Random Access Memory (RAM), Read-Only Memory (ROM), Electrically Erasable Programmable Read-only Memory (EEPROM), flash memory or other memory technology, Compact Disc-Read-Only Memory (CD-ROM,) digital versatile discs (DVD), holographic media or other optical disc storage, magnetic cassettes, magnetic tape, magnetic disk storage, and other magnetic storage devices. These memory components can store data momentarily, temporarily, or permanently. [18] Communications media typically store computer-useable instructions - including data structures and program modules - in a modulated data signal. The term "modulated data signal" refers to a propagated signal that has one or more of its characteristics set or changed to encode information in the signal. An exemplary modulated data signal includes a carrier wave or other transport mechanism. Communications media include any information-delivery media. By way of example but not limitation, communications media include wired media, such as a wired network or direct-wired connection, and wireless media such as acoustic, infrared, radio, microwave, spread-spectrum, and other wireless media technologies. Combinations of the above are included within the scope of computer-readable media. Keyword Expression Language In an implementation of an embodiment of the present invention, a keyword expression language is provided. With the keyword expression language, an advertiser can use regular expression-type syntax keyword sets like Panasonic® TD- H{a-b}+{0-9}*. Similarly, a user can look for all models of the Canon® PowerShot® cameras by issuing a query of the form: Canon® PowerShot® {A-Z}+{0-9}{0-9}{0- 9}*. In addition, the keyword expression language standard provides sets of tokens that represent a set of related keywords. For example, {gender} and {location} are interpreted as the complete set of keywords belonging to the token class, {gender} matches with "male", "female", "women", "boy", "man", "girl", and so on. [20] The keyword expression language chaining and constraining of concepts. For example, {location