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token.sk
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token.sk
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namespace Skew {
enum PassKind {
LEXING
TOKEN_PROCESSING
}
class LexingPass : Pass {
over kind PassKind {
return .LEXING
}
over run(context PassContext) {
for source in context.inputs {
context.tokens.append(tokenize(context.log, source))
}
}
}
class TokenProcessingPass : Pass {
over kind PassKind {
return .TOKEN_PROCESSING
}
over run(context PassContext) {
for tokens in context.tokens {
prepareTokens(tokens)
}
}
}
class Token {
var range Range
var kind TokenKind
def firstCodeUnit int {
if kind == .END_OF_FILE {
return 0
}
assert(range.start < range.source.contents.count)
return range.source.contents[range.start]
}
}
var REMOVE_NEWLINE_BEFORE IntMap<int> = {
TokenKind.COLON: 0,
TokenKind.COMMA: 0,
TokenKind.DOT: 0,
TokenKind.NEWLINE: 0,
TokenKind.QUESTION_MARK: 0,
TokenKind.RIGHT_BRACKET: 0,
TokenKind.RIGHT_PARENTHESIS: 0,
}
def prepareTokens(tokens List<Token>) {
var previousKind TokenKind = .NULL
var stack List<Token> = []
var count = 0
for i in 0..tokens.count {
var token = tokens[i]
# Skip null placeholders after tokens that start with a greater than. Each
# token that may need to split has enough nulls after it for all the pieces.
# It's a lot faster to remove null gaps during token preparation than to
# insert pieces in the middle of the token stream (O(n) vs O(n^2)).
if token == null {
continue
}
# Compress tokens to eliminate unused null gaps
tokens[count++] = token
# Tokens that start with a greater than may need to be split
var tokenKind = token.kind
var tokenStartsWithGreaterThan = token.firstCodeUnit == '>'
# Remove tokens from the stack if they aren't working out
while !stack.isEmpty {
var top = stack.last
var topKind = top.kind
# Stop parsing a type if we find a token that no type expression uses
if topKind == .LESS_THAN && tokenKind != .LESS_THAN && tokenKind != .IDENTIFIER && tokenKind != .COMMA && tokenKind != .DYNAMIC &&
tokenKind != .DOT && tokenKind != .LEFT_PARENTHESIS && tokenKind != .RIGHT_PARENTHESIS && !tokenStartsWithGreaterThan {
stack.removeLast
} else {
break
}
}
# Group open
if tokenKind == .LEFT_PARENTHESIS || tokenKind == .LEFT_BRACE || tokenKind == .LEFT_BRACKET || tokenKind == .LESS_THAN {
stack.append(token)
}
# Group close
else if tokenKind == .RIGHT_PARENTHESIS || tokenKind == .RIGHT_BRACE || tokenKind == .RIGHT_BRACKET || tokenStartsWithGreaterThan {
# Search for a matching opposite token
while !stack.isEmpty {
var top = stack.last
var topKind = top.kind
# Don't match closing angle brackets that don't work since they are just operators
if tokenStartsWithGreaterThan && topKind != .LESS_THAN {
break
}
# Consume the current token
stack.removeLast
# Special-case angle brackets matches
if topKind == .LESS_THAN {
# Remove tentative matches that didn't work out
if !tokenStartsWithGreaterThan {
continue
}
# Break apart operators that start with a closing angle bracket
if tokenKind != .GREATER_THAN {
var range = token.range
var start = range.start
assert(i + 1 < tokens.count)
assert(tokens[i + 1] == null)
assert(
tokenKind == .ASSIGN_SHIFT_RIGHT ||
tokenKind == .ASSIGN_UNSIGNED_SHIFT_RIGHT ||
tokenKind == .GREATER_THAN_OR_EQUAL ||
tokenKind == .SHIFT_RIGHT ||
tokenKind == .UNSIGNED_SHIFT_RIGHT)
tokens[i + 1] = Token.new(Range.new(range.source, start + 1, range.end),
tokenKind == .SHIFT_RIGHT ? .GREATER_THAN :
tokenKind == .UNSIGNED_SHIFT_RIGHT ? .SHIFT_RIGHT :
tokenKind == .GREATER_THAN_OR_EQUAL ? .ASSIGN :
tokenKind == .ASSIGN_SHIFT_RIGHT ? .GREATER_THAN_OR_EQUAL :
tokenKind == .ASSIGN_UNSIGNED_SHIFT_RIGHT ? .SHIFT_RIGHT :
.NULL)
token.range = Range.new(range.source, start, start + 1)
}
# Convert < and > into bounds for type parameter lists
top.kind = .START_PARAMETER_LIST
token.kind = .END_PARAMETER_LIST
tokenKind = .END_PARAMETER_LIST
}
# Stop the search since we found a match
break
}
}
# Remove newlines based on the previous token to enable line continuations.
# Make sure to be conservative. We want to be like Python, not like
# JavaScript ASI! Anything that is at all ambiguous should be disallowed.
if previousKind == .NEWLINE && tokenKind in REMOVE_NEWLINE_BEFORE {
tokens[count - 2] = token
count--
}
previousKind = tokenKind
}
# Trim off the remaining tokens due to null gap removal
while tokens.count > count {
tokens.removeLast
}
}
enum TokenKind {
def toString string {
assert(self in _toString)
return _toString[self]
}
}
namespace TokenKind {
const _toString IntMap<string> = {
COMMENT: "comment",
NEWLINE: "\"\\n\"",
WHITESPACE: "whitespace",
AS: "\"as\"",
BREAK: "\"break\"",
CASE: "\"case\"",
CATCH: "\"catch\"",
CLASS: "\"class\"",
CONST: "\"const\"",
CONTINUE: "\"continue\"",
DEF: "\"def\"",
DEFAULT: "\"default\"",
DYNAMIC: "\"dynamic\"",
ELSE: "\"else\"",
ENUM: "\"enum\"",
FALSE: "\"false\"",
FINALLY: "\"finally\"",
FOR: "\"for\"",
IF: "\"if\"",
IN: "\"in\"",
INTERFACE: "\"interface\"",
IS: "\"is\"",
NAMESPACE: "\"namespace\"",
NULL: "\"null\"",
OVER: "\"over\"",
RETURN: "\"return\"",
SUPER: "\"super\"",
SWITCH: "\"switch\"",
THROW: "\"throw\"",
TRUE: "\"true\"",
TRY: "\"try\"",
VAR: "\"var\"",
WHILE: "\"while\"",
ARROW: "\"=>\"",
ASSIGN: "\"=\"",
ASSIGN_BITWISE_AND: "\"&=\"",
ASSIGN_BITWISE_OR: "\"|=\"",
ASSIGN_BITWISE_XOR: "\"^=\"",
ASSIGN_DIVIDE: "\"/=\"",
ASSIGN_INDEX: "\"[]=\"",
ASSIGN_MINUS: "\"-=\"",
ASSIGN_MULTIPLY: "\"*=\"",
ASSIGN_PLUS: "\"+=\"",
ASSIGN_POWER: "\"**=\"",
ASSIGN_REMAINDER: "\"%=\"",
ASSIGN_SHIFT_LEFT: "\"<<=\"",
ASSIGN_SHIFT_RIGHT: "\">>=\"",
ASSIGN_UNSIGNED_SHIFT_RIGHT: "\">>>=\"",
BITWISE_AND: "\"&\"",
BITWISE_OR: "\"|\"",
BITWISE_XOR: "\"^\"",
COLON: "\":\"",
COMMA: "\",\"",
COMPARE: "\"<=>\"",
DECREMENT: "\"--\"",
DIVIDE: "\"/\"",
DOT: "\".\"",
DOT_DOT: "\"..\"",
DOUBLE_COLON: "\"::\"",
EQUAL: "\"==\"",
GREATER_THAN: "\">\"",
GREATER_THAN_OR_EQUAL: "\">=\"",
INCREMENT: "\"++\"",
INDEX: "\"[]\"",
LEFT_BRACE: "\"{\"",
LEFT_BRACKET: "\"[\"",
LEFT_PARENTHESIS: "\"(\"",
LESS_THAN: "\"<\"",
LESS_THAN_OR_EQUAL: "\"<=\"",
LIST: "\"[...]\"",
LIST_NEW: "\"[new]\"",
LOGICAL_AND: "\"&&\"",
LOGICAL_OR: "\"||\"",
MINUS: "\"-\"",
MULTIPLY: "\"*\"",
NOT: "\"!\"",
NOT_EQUAL: "\"!=\"",
NULL_DOT: "\"?.\"",
NULL_JOIN: "\"??\"",
PLUS: "\"+\"",
POWER: "\"**\"",
QUESTION_MARK: "\"?\"",
REMAINDER: "\"%\"",
RIGHT_BRACE: "\"}\"",
RIGHT_BRACKET: "\"]\"",
RIGHT_PARENTHESIS: "\")\"",
SEMICOLON: "\";\"",
SET: "\"{...}\"",
SET_NEW: "\"{new}\"",
SHIFT_LEFT: "\"<<\"",
SHIFT_RIGHT: "\">>\"",
TILDE: "\"~\"",
UNSIGNED_SHIFT_RIGHT: "\">>>\"",
ANNOTATION: "annotation",
CHARACTER: "character",
DOUBLE: "double",
END_OF_FILE: "end of input",
IDENTIFIER: "identifier",
INT: "integer",
INT_BINARY: "integer",
INT_HEX: "integer",
INT_OCTAL: "integer",
STRING: "string",
}
}
}