Syntax Grammar

The MRI syntax grammar doesn't lend itself to precise formal documentation in the typical fashion for programming languages, because the parsing process is implemented in a fairly complicated way that can occasionally be inconsistent and/or buggy, and to fully describe what the permitted syntax is would require a myriad of detailed rules for exceptional circumstances that wouldn't be much use to anyone.

However, this is not a problem, because we can easily describe the syntax of Ruby by showing all the important elements, but point out where odd, but harmless, exceptional behaviours can occur, and leave these behaviours undefined. This way gives the intent of the syntax grammar without getting bogged down in implementation limitations.

#Statements

A statement is any Ruby expression terminated either by ; or a newline character, and a block of statements is executed iteratively in the typical fashion.

A block of statements can be nested within another Ruby expression by enclosing it within ( and ), or by using a begin/end expression (i.e. enclosing between begin and end, note that begin/end expressions also have some other specific behaviours). The return value of a block of statements is the return value of the last statement in the block.

A Ruby sourcefile is a block of statements.

##Newline terminators

Statements/newlines 4 levels Operator conflict resolution Do/brace/bracket/paren conflict resolution reserved words command call brace args, do blocks, and chains Character processing details - newlines, eof void/value expressions