walt-syntax v0.7.0
Walt Syntax
Syntax definitions for the Walt, WebAssembly Alternative Syntax.
Syntax
Numbers
- decimals
1, 20, 42
- floating point
1.1
- hex
0xFF
Stings
- character literals
'x'
- words
"hello world!"
*
*words require a memory to be present in the module
Types
i32
i64
f32
f64
u32
u64
Keywords
Most JavaScript keywords are supported and have similar(when possible) semantics.
break
if
else
import
as
from
export
return
switch
case
default
const
let
for
continue
do
while
function
Native
Abstract Syntax Tree
Syntax nodes are Plain Old JavaScript Objects.
export type NodeType = {
range: Marker[],
Type: string,
type: string | null,
value: string,
meta: { [string]: any },
params: NodeType[],
};
Type
is a pre-defined walt-specific string constant. For a full list of these constants, refer to the source. type
(lowercase) is the WebAssembly type and must be one of i32 | f32 | i64 | f64
or the literal null
value which represents a void value. Note: Any valid string could be the type
value but only the 5 supported values above will compile.
params
are the children of the node.
meta
is used to hold information about the node which is not present in the source program and is either inferred or implied. For example a struct type definition may contain the key value offsets which are used to compile it's property look ups.
Compile-able AST Types
While many different nodes are possible a strict subset of node Type
are considered valid by the generator and are compile-able.
Syntax.Typedef,
Syntax.Import,
Syntax.Export,
Syntax.FunctionDeclaration,
Syntax.FunctionCall,
Syntax.IndirectFunctionCall,
Syntax.Constant,
Syntax.BinaryExpression,
Syntax.TernaryExpression,
Syntax.IfThenElse,
Syntax.Else,
Syntax.Select,
Syntax.Block,
Syntax.Identifier,
Syntax.FunctionIdentifier,
Syntax.FunctionPointer,
Syntax.ReturnStatement,
Syntax.Declaration,
Syntax.ArraySubscript,
Syntax.Access,
Syntax.Assignment,
Syntax.MemoryAssignment,
Syntax.Loop,
Syntax.Break,
Syntax.TypeCast,
Syntax.Noop,
Syntax.NativeMethod