Lily Extras
This is a personal collection of useful libraries and examples for the Lily programming language. There is a binary extension xstr, and a lexical scanner that uses its string iterator. The lexical scanner is used to parse JSON (with comments ;)) - the json module is a nice example in itself of how to use enums for fun and profit.
xstr
If Lily has been properly installed, then 'cmake . && make' will give you 'xstr.so' in the current directory.
###define next(s: String, index: Integer): Tuple[String,Integer]
Grab the following character at index. Returns a tuple containing the character at the index, and the index of the next character.
The returned index is -1 for the last character; thereafter ["",-1] is returned.
###define size (s: String): Integer
Number of characters in a string
define readall (f: File): String
Read the whole of a file as a string. Does not check whether the resulting string is valid UTF-8.
###define parse_i (s: String, base: *Integer=10): Option[Integer]
Like String.parse_i, except that you can provide a base (default 10)
define parse_d (s: String): Option[Double]
Convert a string to a Double, returning None if unsuccesful
###define shell (cmd: String): String
Read all the output of a shell command using popen
###define print (values:1...)
Print several values - not restricted to one value like the global of this name.
###define concat(delim: String, values:1...):String
Concatenate some arbitrary values using the single-character delimiter
###define exit(code: Integer)
Exit the program with the given return code
scan
Lexical scanners are my favourite text processing tools. They break a string up into tokens, 'identifier','number','string','character', etc. This one ignores whitespace and can be taught to ignore comments as well.
Have a look at test-scan.lly for usage.
json
Showing how enum naturally expresses recursive data!
json_parse.lly
An example showing how straightforward it is to parse JSON source into the data format defined by json.lly.
This shows more advanced features of scan, like skipping line and block comments.
shell.lly
Showing off some of xstr's capabilities, like Python-style formatting and executing shell commands.
skelgen.lly
This I present as a non-trivial Lily application. It's still very young, but its purpose is to build a skeleton for implementing a Lily C extension.
Go into the os directory, and run lily ../skelgen.lly .. It will read os.help and generate lily_os.c. That's it - you fill in the gaps and run dyna_tools.py to create the dispatch table.
It can be used also as a quick tool to look at how an individual C function implementing a signature would look like:
xstr$ lily skelgen.lly -s '(a: String): String'
test (a: String): String
void lily_skelgen__test (lily_state *s)
{
const char* a = lily_arg_string_raw(s,0);
const char* return_value = "";
lily_return_string_raw(s,return_value);
}