Method, system and computer program for syntax validation

A computer system for validating a syntactical statement comprising:

• a stored syntax tree representing all possible syntax options by means of a network of junction nodes and data nodes between a root node and an end node, such that all paths through the tree lead to the end node, whereby said syntactical statement is initially passed to the root node;
• means for parsing said syntactical statement into elementary tokens in the root node;
• a table to store the tokens, and entries representing the end node of the syntactical statement;
• means for maintaining the location of a current node in the syntax tree, whereby said current node is initially the root node;
• means for returning potential nodes that can be selected from the current node and their distances from the current node;
• means for comparing the potential nodes to the stored tokens and means for selecting a potential node of said potential nodes corresponding to one of said stored tokens if such a corresponding node exists;
• and
• means for updating the location of the current node;
• whereby said syntactical statement is valid if said end node is reached.

A computer-implemented syntax checker comprising:

• a stored syntax tree representing a body of valid syntax;
• and
• a table for holding elementary tokens of syntax making up a syntactical statement to be checked;
• said syntax tree comprising root and end node objects joined by a network of junction node objects and data node objects, said data node objects representing options in the syntax including tokens, such that each junction node object may link to an unlimited number of other junction node objects and data node objects, and each data node object only links to a singular junction node object, whereby all pathways through the network eventually terminate in said end node object;
• each of said junction node objects, being effective to evaluate linked data node options following said junction node object so that any tokens in said table corresponding to a linked data node object are marked as “found”,
• whereby said syntactical statement is progressively compared with said syntax tree either until said end node is reached, indicating the syntax of the statement is valid, or until a corresponding data object is not found, indicating said syntax is not valid.

A computer program recorded on a memory device consisting of instructions which, when executed on a computer, perform a method of validating a syntactical statement employing a stored syntax tree representing all possible syntax options by means of a network of junction nodes and data nodes between a root node and an end node, such that all paths through the tree lead to the end node, said method comprising the steps of:

• passing said syntactical statement to the root node and parsing said syntactical statement into elementary tokens in the root node;
• maintaining the location of a current node in the syntax free, whereby said current node is initially the root node;
• returning potential nodes that can be selected from the current node and their distances from the current node;
• in response to said returning step, comparing the potential nodes to the stored tokens and selecting a potential node corresponding to one of said stored tokens if such a corresponding node exists;
• updating the location of the current node to that of a selected node,
• repeating said returning, comparing and selecting steps wherein the syntactical statement is validated if the end node is reached.