leo/compiler/ast/README.md

leo-ast

This directory contains the code for the AST of a Leo Program.

Node Types

There are several types of nodes in the AST that then have further breakdowns.

All nodes store a Span, which is useful for tracking the lines and columns of where the node was taken from in the Leo Program.

Program/File

The top level nodes in a Leo Program.

Imports

Represents an import statement in a Leo Program. A list of these are stored on the Program. It stores the path to an import and what is being imported.

NOTE: The import does not contain the source code of the imported Leo Program.

Circuits

A circuit node represents a defined Circuit in a Leo Program. An order-preserving map of these are stored on the Program. Contains the Circuit's name, as well as its members. The members are a function, or a variable, or a constant. For all of them the Circuit preserves their names.

Annotations

An annotation node is a decorator that can be applied to a function. Stored on the function themselves despite being a top-level node. The node stores the name of the annotation, as well as any args passed to it.

Functions

A function node represents a defined function in a Leo Program. An order-preserving map of these are stored on the Program. A function node stores the following information:

• The annotations applied to the function.
• An identifier the name of the function.
• The inputs to the function, both their names and types.
• The output of the function as a type if it exists.
• The function body stored as a block statement.

Global Consts

A global const is a bit special and has no special node for itself, but rather is a definition statement. An order-preserving map of these are stored on the Program.

Types

The different types in a Leo Program. Types themselves are not a node, but rather just information to be stored on a node.

Address

The address type follows the BIP_0173 format starting with aleo1.

Boolean

The boolean type consists of two values true and false.

Char

The char type resents a character from the inclusive range [0, 10FFFF].

Field

The field type an unsigned number less than the modulus of the field.

Group

The group type a set of affine points on the elliptic curve passed.

IntegerType

The integer type represents a range of integer types.

U8

A integer in the inclusive range [0, 255].

U16

A integer in the inclusive range [0, 65535].

U32

A integer in the inclusive range [0, 4294967295].

U64

A integer in the inclusive range [0, 18446744073709551615].

U128

A integer in the inclusive range [0, 340282366920938463463374607431768211455].

I8

A integer in the inclusive range [-128, 127].

I16

A integer in the inclusive range [-32768, 32767].

I32

A integer in the inclusive range [-2147483648, 2147483647].

I64

A integer in the inclusive range [-9223372036854775808, 9223372036854775807].

I128

A integer in the inclusive range [-170141183460469231731687303715884105728, 170141183460469231731687303715884105727].

Array

The array type contains another type, then the number of elements of that type greater than 0 for monodimensional arrays, or a list of such numbers of elements for multidimensional arrays.

Tuple

The tuple type contains n types, where n is greater than or equal to 0.

Identifier

An identifier type is either a circuit type or a type alias; every circuit type represents a different type.

SelfType

The self type represented by Self and only usable inside a circuit.

Statements

The statement level nodes in a Leo Program.

Assignment Statements

An assignment statement node stores the following:

• The operation.
  • =
  • +=
  • -=
  • *=
  • /=
  • **=
  • &&=
  • ||=
• The assignee which is a variable that has context of any access expressions on it.
• The value which is an expression.

Block Statements

A block statement node stores the following:

• The list of statements inside the block.

Conditional Statements

A conditional statement node stores the following:

• The condition which is an expression.
• The block statement.
• The next block of the conditional if it exists.

Console Statements

A console statement node stores the following:

• The console function being called which stores the type of console function it is and its arguments.

Definition Statements

A definition statement node stores the following:

• The declaration type:
  • let for mutable definitions.
  • const for cosntant definitions.
• The names of the variables defined.
• The optional type.
• The values to be assigned to the varaibles.

Expression Statements

An expression statement node stores the following:

• The expression.

Iteration Statements

A iteration statement node stores the following:

• The loop iterator variable name.
• The expression to define the starting loop value.
• The expression to define the stopping loop value.
• A flag indicating whether the stopping value is inclusive or not.
• The block to run for the loop.

Return Statements

A return statement node stores the following:

• The expression that is being returned.

Expressions

The expression nodes in a Leo Program.

ArrayAccess Expressions

An array access expression node stores the following:

• The array expression.
• The index represented by an expression.

ArrayInit Expressions

An array init expression node stores the following:

• The element expression to fill the array with.
• The dimensions of the array to build.

ArrayInline Expressions

An array inline expression node stores the following:

• The elements of an array, each of which is either a spread or an expression.

ArrayRangeAccess Expressions

An array range access expression node stores the following:

• The array expression.
• The optional left side of the range of the array bounds to access.
• The optional right side of the range of the array bounds to access.

Binary Expressions

A binary expression node stores the following:

• The left side of the expression.
• The right side of the expression.
• The binary operation of the expression:
  • +
  • -
  • *
  • /
  • **
  • ||
  • &&
  • ==
  • !=
  • >=
  • >
  • <=
  • <

Call Expressions

A call expression node stores the following:

• The function expression being called.
• The aruments a list of expressions.

CircuitInit Expressions

A circuit init expression node stores the following:

• The name of the circuit expression being initialized.
• The arguments a list of expressions.

MemberAccess Expressions

A member access expression node stores the following:

• The expression being accessed.
• The name of the member being accessed.
• The optional inferred type.

StaticAccess Expressions

A static function access expression node stores the following:

• The expression being accessed.
• The name of the member being statically accessed.
• The optional inferred type.

Identifier Expressions

An identifer expression node stores the following:

• An identifier stores the string name.

Ternary Expressions

A ternary expression node stores the following:

• The condition of the ternary stored as an expression.
• The expression returned if the condition is true.
• The expression returned if the condition is false.

TupleAccess Expressions

A tuple access expression node stores the following:

• The tuple expression being accessed.
• The index a positive number greater than or equal to 0.

TupleInit Expressions

A tuple init expression node stores the following:

• The element expressions to fill the tuple with.

Unary Expressions

An unary expression node stores the following:

• The inner expression.
• The unary operator:
  • !
  • -

Value Expressions

A value expression node stores one of the following:

• Address and its value and span.
• Boolean and its value and span.
• Char and its value and span.
• Field and its value and span.
• Group and its value and span.
• Implicit and its value and span.
• Integer and its value and span.
• String and its value and span.