Syntax Checker Exercise

Users can check the correctness of the standard nomenclature syntax. The Syntax Checker uses a context-free parser to detect deviations from the standard nomenclature syntax in the input.

1. Paste the text AB026906.1:c.274G>T into the submission field.

2. Press the Submit button.

The result: The syntax of this variant is OK!

3. Paste the text AB026906.1:c.274G->T into the submission field.

4. Press the Submit button.

The error message "Expected ">" (at char 17), (line:1, col:18)" describes what the parser expects based on the nomenclature syntax. The position of the deviation is also indicated by a caret (^) below the description.

The standard nomenclature does not allow the arrow -> in substitution descriptions.

The parser of the syntax checker is already aware of the new description format for complex variants using curly braces for substitutions in duplicated regions:

5. Paste the text NG_012337.1(SDHD_v1):c.55_72dup{62T>G} into the submission field.

6. Press the Submit button.

Checks of these descriptions have not yet been implemented in the Name Checker.

7. Remove the symbol > from the previous description and submit it.

Due to the complexity of the syntax, the character(s) expected by the parser may be incorrect.