water.rapids

Class Rapids

java.lang.Object

water.rapids.Rapids

public class Rapids
extends java.lang.Object

Rapids is an interpreter of abstract syntax trees.

This file contains the AstRoot parser and parser helper functions. AstRoot Execution starts in the AstExec file, but spreads throughout Rapids.

Trees have a Lisp-like structure with the following "reserved" special characters:

'('

a nested function application expression till ')'

'{'

a nested function definition expression till '}'

'['

a numeric or string list expression, till ']'

'"'

a String (double quote)

"'"

a String (single quote)

digits:

a number

letters or other specials:

an ID

Variables are lexically scoped inside 'let' expressions or at the top-level looked-up in the DKV directly (and must refer to a known type that is valid on the execution stack).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Rapids.IllegalASTException

Method Summary

Modifier and Type	Method and Description
static Val	exec(java.lang.String rapids) Execute a single rapids call in a short-lived session
static Val	exec(java.lang.String rapids, Session session) Compute and return a value in this session.
static AstRoot	parse(java.lang.String rapids) Parse a Rapids expression string into an Abstract Syntax Tree object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

parse

public static AstRoot parse(java.lang.String rapids)

Parse a Rapids expression string into an Abstract Syntax Tree object.

Parameters:

rapids - expression to parse

exec

public static Val exec(java.lang.String rapids)

Execute a single rapids call in a short-lived session

Parameters:

rapids - expression to parse

exec

public static Val exec(java.lang.String rapids,
                       Session session)

Compute and return a value in this session. Any returned frame shares Vecs with the session (is not deep copied), and so must be deleted by the caller (with a Rapids "rm" call) or will disappear on session exit, or is a normal global frame.

Parameters:

rapids - expression to parse