Regex that matches Camel and Pascal Case

Question

I'm about to write a parser for a language that's supposed to have strict syntactic rules about naming of types, variables and such. For example all classes must be PascalCase, and all variables/parameter names and other identifiers must be camelCase. For example `HTMLParser` is not allowed and must be named `HtmlParser`. Any ideas for a regexp that can match something that is PascalCase, but does not have two capital letters in it?

Accepted Answer

camelCase:

```
^[a-z]+(?:[A-Z][a-z]+)*$
```

PascalCase:

```
^[A-Z][a-z]+(?:[A-Z][a-z]+)*$
```

Regex that matches Camel and Pascal Case

Solution

Problem