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import {
ASTNode,
NodeType,
ParserCtx,
Token,
TokenSubType,
TokenType,
} from "./common";
import { Lex } from "./lexer";
/*
start
if no 'lastName'
then:
expect nextToken to be a name
lastName = nextToken
goto start
else:
if nextToken is name
then:
// we already have a lastName
mutate last element of stack to push lastName as child
lastName = nextToken
goto start
else:
//nextToken is openParen or close paren
if nextToken is closeParen
then:
set last element of stack as child of prev element on stack
pop stack
// [stack[last - 1].children.push(stack.pop)
goto start
else if nextToken is openParen:
push lastName onto stack
goto start
finally:
// only one element remains on the stack
return stack[0]
CALL ( param, CALL2 ( param2 ) )
param2 ret call2 param ret call
| call
|-- param
|-- | call2
|-- param2
*/
export type Error<T extends string> = ASTNode<
NodeType.PARSER_ERROR,
"Error",
T,
[]
>;
export type PushChild<Node extends ASTNode, Child extends ASTNode> = {
type: Node["type"];
value: Node["value"];
name: Node["name"];
children: [...Node["children"], Child];
};
export type PushChildToLastElementOfStack<
Stack extends ParserCtx["stack"],
Child extends ASTNode
> = Stack extends [...infer Head, infer Tail extends ASTNode]
? [...Head, PushChild<Tail, Child>]
: Stack extends [infer Only extends ASTNode]
? [PushChild<Only, Child>]
: never;
export type PushChildToSecondLastElementOfStack<
Stack extends ParserCtx["stack"],
Child extends ASTNode
> = Stack extends [
...infer Head,
infer Tail extends ASTNode,
infer Final extends ASTNode
]
? [...Head, PushChild<Tail, Child>, Final]
: Stack extends [infer Only extends ASTNode, infer Final extends ASTNode]
? [PushChild<Only, Child>, Final]
: never;
export type GetLastOnStack<Stack extends ParserCtx["stack"]> = Stack extends [
...infer Head,
infer Tail extends ASTNode
]
? Tail
: Stack extends [infer Only extends ASTNode]
? Only
: never;
export type StackWithoutLast<Stack extends ParserCtx["stack"]> = Stack extends [
...infer Head extends ASTNode[],
infer Tail
]
? [...Head]
: Stack extends [infer Only extends ASTNode]
? []
: never;
type NULL_SENTINEL = {
NULL: true;
};
export type ParseNumberLiteral<T extends string> =
T extends `${infer Inner extends number}` ? Inner : NULL_SENTINEL;
export type ParseStringLiteral<T extends string> =
T extends `"${infer Inner extends string}"` ? Inner : NULL_SENTINEL;
export type ResolveNodeFromToken<_Token extends Token> = ParseNumberLiteral<
_Token["name"]
> extends number
? ASTNode<NodeType.INT, "", ParseNumberLiteral<_Token["name"]>, []>
: ParseStringLiteral<_Token["name"]> extends string
? ASTNode<NodeType.INT, "", ParseStringLiteral<_Token["name"]>, []>
: ASTNode<NodeType.EXT, _Token["name"], null, []>;
export type _Parse<Ctx extends ParserCtx> = Ctx["remainingTokens"] extends [
infer Head extends Token,
...infer Tail extends readonly Token[]
]
? Ctx["lastToken"] extends Token
? Head["type"] extends TokenType.NAME
? // we already have a lastName
// mutate last element of stack to push lastName as child
// lastName = nextToken
// goto start
_Parse<{
lastToken: Head;
remainingTokens: Tail;
stack: PushChildToLastElementOfStack<
Ctx["stack"],
ResolveNodeFromToken<Ctx["lastToken"]>
>;
}>
: //nextToken is openParen or close paren
Head["type"] extends TokenType.CLOSE_PAREN
? // handle lastName
// set last element of stack as child of prev element on stack
// pop stack
// [stack[last - 1].children.push(stack.pop)
// goto start
_Parse<{
lastToken: null;
remainingTokens: Tail;
// first push the last name onto the children of the top
// then push the top onto the children of the next
// then remove the top
stack: StackWithoutLast<
PushChildToSecondLastElementOfStack<
Ctx["stack"],
PushChild<
GetLastOnStack<Ctx["stack"]>,
ResolveNodeFromToken<Ctx["lastToken"]>
>
>
>;
}>
: Head["type"] extends TokenType.OPEN_PAREN
? // push lastName onto stack
// goto start
_Parse<{
lastToken: null;
remainingTokens: Tail;
stack: [...Ctx["stack"], ResolveNodeFromToken<Ctx["lastToken"]>];
}>
: Ctx & Error<`Was not expecting ${Head["type"]}`>
: // expect nextToken to be a name or close paren
Head["type"] extends TokenType.NAME
? // lastName = nextToken
// goto start
_Parse<{
lastToken: Head;
remainingTokens: Tail;
stack: Ctx["stack"];
}>
: Head["type"] extends TokenType.CLOSE_PAREN
? _Parse<{
lastToken: null;
remainingTokens: Tail;
// push the top onto the children of the next
// then remove the top
stack: StackWithoutLast<
PushChildToSecondLastElementOfStack<
Ctx["stack"],
GetLastOnStack<Ctx["stack"]>
>
>;
}>
: Ctx &
Error<`Expected nextToken to be a name or close paren at ${Head["type"]}`>
: Ctx["lastToken"] extends Token
? // case where we ended with a name
_Parse<{
lastToken: null;
remainingTokens: [];
stack: PushChildToLastElementOfStack<
Ctx["stack"],
ResolveNodeFromToken<Ctx["lastToken"]>
>;
}>
: Ctx["stack"][0];
export type Parse<Raw extends readonly Token[]> = _Parse<{
lastToken: null;
remainingTokens: Raw;
stack: [ASTNode<NodeType.ROOT, "ROOT", null, []>];
}>;
const test_result = null as unknown as Parse<Lex<`test(135)`>>;
|
