| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package net.starlark.java.syntax; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.ImmutableMap; |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Stack; |
| |
| /** A scanner for Starlark. */ |
| final class Lexer { |
| |
| // --- These fields are accessed directly by the parser: --- |
| |
| // Mapping from file offsets to Locations. |
| final FileLocations locs; |
| |
| // Information about current token. Updated by nextToken. |
| // raw and value are defined only for STRING, INT, FLOAT, IDENTIFIER, and COMMENT. |
| // TODO(adonovan): rename s/xyz/tokenXyz/ |
| TokenKind kind; |
| int start; // start offset |
| int end; // end offset |
| String raw; // source text of token |
| Object value; // String, Integer/Long/BigInteger, or Double value of token |
| |
| // --- end of parser-visible fields --- |
| |
| private final List<SyntaxError> errors; |
| |
| // Input buffer and position |
| private final char[] buffer; |
| private int pos; |
| |
| private final FileOptions options; |
| |
| // The stack of enclosing indentation levels in spaces. |
| // The first (outermost) element is always zero. |
| private final Stack<Integer> indentStack = new Stack<>(); |
| |
| private final List<Comment> comments; |
| |
| // The number of unclosed open-parens ("(", '{', '[') at the current point in |
| // the stream. Whitespace is handled differently when this is nonzero. |
| private int openParenStackDepth = 0; |
| |
| // True after a NEWLINE token. In other words, we are outside an |
| // expression and we have to check the indentation. |
| private boolean checkIndentation; |
| |
| // Number of saved INDENT (>0) or OUTDENT (<0) tokens detected but not yet returned. |
| private int dents; |
| |
| // Characters that can come immediately prior to an '=' character to generate |
| // a different token |
| private static final ImmutableMap<Character, TokenKind> EQUAL_TOKENS = |
| ImmutableMap.<Character, TokenKind>builder() |
| .put('=', TokenKind.EQUALS_EQUALS) |
| .put('!', TokenKind.NOT_EQUALS) |
| .put('>', TokenKind.GREATER_EQUALS) |
| .put('<', TokenKind.LESS_EQUALS) |
| .put('+', TokenKind.PLUS_EQUALS) |
| .put('-', TokenKind.MINUS_EQUALS) |
| .put('*', TokenKind.STAR_EQUALS) |
| .put('/', TokenKind.SLASH_EQUALS) |
| .put('%', TokenKind.PERCENT_EQUALS) |
| .put('^', TokenKind.CARET_EQUALS) |
| .put('&', TokenKind.AMPERSAND_EQUALS) |
| .put('|', TokenKind.PIPE_EQUALS) |
| .build(); |
| |
| // Constructs a lexer which tokenizes the parser input. |
| // Errors are appended to errors. |
| Lexer(ParserInput input, FileOptions options, List<SyntaxError> errors) { |
| this.locs = FileLocations.create(input.getContent(), input.getFile()); |
| this.options = options; |
| this.buffer = input.getContent(); |
| this.pos = 0; |
| this.errors = errors; |
| this.checkIndentation = true; |
| this.comments = new ArrayList<>(); |
| this.dents = 0; |
| |
| indentStack.push(0); |
| } |
| |
| List<Comment> getComments() { |
| return comments; |
| } |
| |
| /** |
| * Reads the next token, updating the Lexer's token fields. It is an error to call nextToken after |
| * an EOF token. |
| */ |
| void nextToken() { |
| boolean afterNewline = kind == TokenKind.NEWLINE; |
| tokenize(); |
| Preconditions.checkState(kind != null); |
| |
| // Like Python, always end with a NEWLINE token, even if no '\n' in input: |
| if (kind == TokenKind.EOF && !afterNewline) { |
| kind = TokenKind.NEWLINE; |
| } |
| } |
| |
| private void popParen() { |
| if (openParenStackDepth == 0) { |
| // TODO(adonovan): fix: the input ')' should not report an indentation error. |
| error("indentation error", pos - 1); |
| } else { |
| openParenStackDepth--; |
| } |
| } |
| |
| private void error(String message, int pos) { |
| errors.add(new SyntaxError(locs.getLocation(pos), message)); |
| } |
| |
| private void setToken(TokenKind kind, int start, int end) { |
| this.kind = kind; |
| this.start = start; |
| this.end = end; |
| this.value = null; |
| this.raw = null; |
| } |
| |
| // setValue sets the value associated with a STRING, FLOAT, INT, |
| // IDENTIFIER, or COMMENT token, and records the raw text of the token. |
| private void setValue(Object value) { |
| this.value = value; |
| this.raw = bufferSlice(start, end); |
| } |
| |
| /** |
| * Parses an end-of-line sequence, handling statement indentation correctly. |
| * |
| * <p>UNIX newlines are assumed (LF). Carriage returns are always ignored. |
| */ |
| private void newline() { |
| if (openParenStackDepth > 0) { |
| newlineInsideExpression(); // in an expression: ignore space |
| } else { |
| checkIndentation = true; |
| setToken(TokenKind.NEWLINE, pos - 1, pos); |
| } |
| } |
| |
| private void newlineInsideExpression() { |
| while (pos < buffer.length) { |
| switch (buffer[pos]) { |
| case ' ': case '\t': case '\r': |
| pos++; |
| break; |
| default: |
| return; |
| } |
| } |
| } |
| |
| /** Computes indentation (updates dent) and advances pos. */ |
| private void computeIndentation() { |
| // we're in a stmt: suck up space at beginning of next line |
| int indentLen = 0; |
| while (pos < buffer.length) { |
| char c = buffer[pos]; |
| if (c == ' ') { |
| indentLen++; |
| pos++; |
| } else if (c == '\r') { |
| pos++; |
| } else if (c == '\t') { |
| indentLen++; |
| pos++; |
| error("Tab characters are not allowed for indentation. Use spaces instead.", pos); |
| } else if (c == '\n') { // entirely blank line: discard |
| indentLen = 0; |
| pos++; |
| } else if (c == '#') { // line containing only indented comment |
| int oldPos = pos; |
| while (pos < buffer.length && c != '\n') { |
| c = buffer[pos++]; |
| } |
| addComment(oldPos, pos - 1); |
| indentLen = 0; |
| } else { // printing character |
| break; |
| } |
| } |
| |
| if (pos == buffer.length) { |
| indentLen = 0; |
| } // trailing space on last line |
| |
| int peekedIndent = indentStack.peek(); |
| if (peekedIndent < indentLen) { // push a level |
| indentStack.push(indentLen); |
| dents++; |
| |
| } else if (peekedIndent > indentLen) { // pop one or more levels |
| while (peekedIndent > indentLen) { |
| indentStack.pop(); |
| dents--; |
| peekedIndent = indentStack.peek(); |
| } |
| |
| if (peekedIndent < indentLen) { |
| error("indentation error", pos - 1); |
| } |
| } |
| } |
| |
| /** |
| * Returns true if current position is in the middle of a triple quote |
| * delimiter (3 x quot), and advances 'pos' by two if so. |
| */ |
| private boolean skipTripleQuote(char quot) { |
| if (peek(0) == quot && peek(1) == quot) { |
| pos += 2; |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| /** |
| * Scans a string literal delimited by 'quot', containing escape sequences. |
| * |
| * <p>ON ENTRY: 'pos' is 1 + the index of the first delimiter |
| * ON EXIT: 'pos' is 1 + the index of the last delimiter. |
| */ |
| private void escapedStringLiteral(char quot, boolean isRaw) { |
| int literalStartPos = isRaw ? pos - 2 : pos - 1; |
| boolean inTriplequote = skipTripleQuote(quot); |
| // more expensive second choice that expands escaped into a buffer |
| StringBuilder literal = new StringBuilder(); |
| while (pos < buffer.length) { |
| char c = buffer[pos]; |
| pos++; |
| switch (c) { |
| case '\n': |
| if (inTriplequote) { |
| literal.append(c); |
| break; |
| } else { |
| error("unclosed string literal", literalStartPos); |
| setToken(TokenKind.STRING, literalStartPos, pos); |
| setValue(literal.toString()); |
| return; |
| } |
| case '\\': |
| if (pos == buffer.length) { |
| error("unclosed string literal", literalStartPos); |
| setToken(TokenKind.STRING, literalStartPos, pos); |
| setValue(literal.toString()); |
| return; |
| } |
| if (isRaw) { |
| // Insert \ and the following character. |
| // As in Python, it means that a raw string can never end with a single \. |
| literal.append('\\'); |
| if (peek(0) == '\r' && peek(1) == '\n') { |
| literal.append("\n"); |
| pos += 2; |
| } else if (buffer[pos] == '\r' || buffer[pos] == '\n') { |
| literal.append("\n"); |
| pos += 1; |
| } else { |
| literal.append(buffer[pos]); |
| pos += 1; |
| } |
| break; |
| } |
| c = buffer[pos]; |
| pos++; |
| switch (c) { |
| case '\r': |
| if (peek(0) == '\n') { |
| pos += 1; |
| break; |
| } else { |
| break; |
| } |
| case '\n': |
| // ignore end of line character |
| break; |
| case 'n': |
| literal.append('\n'); |
| break; |
| case 'r': |
| literal.append('\r'); |
| break; |
| case 't': |
| literal.append('\t'); |
| break; |
| case '\\': |
| literal.append('\\'); |
| break; |
| case '\'': |
| literal.append('\''); |
| break; |
| case '"': |
| literal.append('"'); |
| break; |
| case '0': |
| case '1': |
| case '2': |
| case '3': |
| case '4': |
| case '5': |
| case '6': |
| case '7': |
| { // octal escape |
| int octal = c - '0'; |
| if (pos < buffer.length) { |
| c = buffer[pos]; |
| if (c >= '0' && c <= '7') { |
| pos++; |
| octal = (octal << 3) | (c - '0'); |
| if (pos < buffer.length) { |
| c = buffer[pos]; |
| if (c >= '0' && c <= '7') { |
| pos++; |
| octal = (octal << 3) | (c - '0'); |
| } |
| } |
| } |
| } |
| if (octal > 0xff) { |
| error("octal escape sequence out of range (maximum is \\377)", pos - 1); |
| } |
| literal.append((char) (octal & 0xff)); |
| break; |
| } |
| case 'a': |
| case 'b': |
| case 'f': |
| case 'N': |
| case 'u': |
| case 'U': |
| case 'v': |
| case 'x': |
| // exists in Python but not implemented in Blaze => error |
| error("invalid escape sequence: \\" + c, pos - 1); |
| break; |
| default: |
| // unknown char escape => "\literal" |
| if (options.restrictStringEscapes()) { |
| error( |
| "invalid escape sequence: \\" |
| + c |
| + ". You can enable unknown escape sequences by passing the flag" |
| + " --incompatible_restrict_string_escapes=false", |
| pos - 1); |
| } |
| literal.append('\\'); |
| literal.append(c); |
| break; |
| } |
| break; |
| case '\'': |
| case '"': |
| if (c != quot || (inTriplequote && !skipTripleQuote(quot))) { |
| // Non-matching quote, treat it like a regular char. |
| literal.append(c); |
| } else { |
| // Matching close-delimiter, all done. |
| setToken(TokenKind.STRING, literalStartPos, pos); |
| setValue(literal.toString()); |
| return; |
| } |
| break; |
| default: |
| literal.append(c); |
| break; |
| } |
| } |
| error("unclosed string literal", literalStartPos); |
| setToken(TokenKind.STRING, literalStartPos, pos); |
| setValue(literal.toString()); |
| } |
| |
| /** |
| * Scans a string literal delimited by 'quot'. |
| * |
| * <ul> |
| * <li> ON ENTRY: 'pos' is 1 + the index of the first delimiter |
| * <li> ON EXIT: 'pos' is 1 + the index of the last delimiter. |
| * </ul> |
| * |
| * @param isRaw if true, do not escape the string. |
| */ |
| private void stringLiteral(char quot, boolean isRaw) { |
| int literalStartPos = isRaw ? pos - 2 : pos - 1; |
| int contentStartPos = pos; |
| |
| // Don't even attempt to parse triple-quotes here. |
| if (skipTripleQuote(quot)) { |
| pos -= 2; |
| escapedStringLiteral(quot, isRaw); |
| return; |
| } |
| |
| // first quick optimistic scan for a simple non-escaped string |
| while (pos < buffer.length) { |
| char c = buffer[pos++]; |
| switch (c) { |
| case '\n': |
| error("unclosed string literal", literalStartPos); |
| setToken(TokenKind.STRING, literalStartPos, pos); |
| setValue(bufferSlice(contentStartPos, pos - 1)); |
| return; |
| case '\\': |
| if (isRaw) { |
| if (peek(0) == '\r' && peek(1) == '\n') { |
| // There was a CRLF after the newline. No shortcut possible, since it needs to be |
| // transformed into a single LF. |
| pos = contentStartPos; |
| escapedStringLiteral(quot, true); |
| return; |
| } else { |
| pos++; |
| break; |
| } |
| } |
| // oops, hit an escape, need to start over & build a new string buffer |
| pos = contentStartPos; |
| escapedStringLiteral(quot, false); |
| return; |
| case '\'': |
| case '"': |
| if (c == quot) { |
| // close-quote, all done. |
| setToken(TokenKind.STRING, literalStartPos, pos); |
| setValue(bufferSlice(contentStartPos, pos - 1)); |
| return; |
| } |
| break; |
| default: // fall out |
| } |
| } |
| |
| // If the current position is beyond the end of the file, need to move it backwards |
| // Possible if the file ends with `r"\` (unclosed raw string literal with a backslash) |
| if (pos > buffer.length) { |
| pos = buffer.length; |
| } |
| |
| error("unclosed string literal", literalStartPos); |
| setToken(TokenKind.STRING, literalStartPos, pos); |
| setValue(bufferSlice(contentStartPos, pos)); |
| } |
| |
| private static final Map<String, TokenKind> keywordMap = new HashMap<>(); |
| |
| static { |
| keywordMap.put("and", TokenKind.AND); |
| keywordMap.put("as", TokenKind.AS); |
| keywordMap.put("assert", TokenKind.ASSERT); |
| keywordMap.put("break", TokenKind.BREAK); |
| keywordMap.put("class", TokenKind.CLASS); |
| keywordMap.put("continue", TokenKind.CONTINUE); |
| keywordMap.put("def", TokenKind.DEF); |
| keywordMap.put("del", TokenKind.DEL); |
| keywordMap.put("elif", TokenKind.ELIF); |
| keywordMap.put("else", TokenKind.ELSE); |
| keywordMap.put("except", TokenKind.EXCEPT); |
| keywordMap.put("finally", TokenKind.FINALLY); |
| keywordMap.put("for", TokenKind.FOR); |
| keywordMap.put("from", TokenKind.FROM); |
| keywordMap.put("global", TokenKind.GLOBAL); |
| keywordMap.put("if", TokenKind.IF); |
| keywordMap.put("import", TokenKind.IMPORT); |
| keywordMap.put("in", TokenKind.IN); |
| keywordMap.put("is", TokenKind.IS); |
| keywordMap.put("lambda", TokenKind.LAMBDA); |
| keywordMap.put("load", TokenKind.LOAD); |
| keywordMap.put("nonlocal", TokenKind.NONLOCAL); |
| keywordMap.put("not", TokenKind.NOT); |
| keywordMap.put("or", TokenKind.OR); |
| keywordMap.put("pass", TokenKind.PASS); |
| keywordMap.put("raise", TokenKind.RAISE); |
| keywordMap.put("return", TokenKind.RETURN); |
| keywordMap.put("try", TokenKind.TRY); |
| keywordMap.put("while", TokenKind.WHILE); |
| keywordMap.put("with", TokenKind.WITH); |
| keywordMap.put("yield", TokenKind.YIELD); |
| } |
| |
| /** |
| * Scans an identifier or keyword. |
| * |
| * <p>ON ENTRY: 'pos' is 1 + the index of the first char in the identifier. |
| * ON EXIT: 'pos' is 1 + the index of the last char in the identifier. |
| */ |
| private void identifierOrKeyword() { |
| int oldPos = pos - 1; |
| String id = scanIdentifier(); |
| TokenKind kind = keywordMap.get(id); |
| if (kind == null) { |
| setToken(TokenKind.IDENTIFIER, oldPos, pos); |
| setValue(id); |
| } else { |
| setToken(kind, oldPos, pos); |
| } |
| } |
| |
| private String scanIdentifier() { |
| // Keep consistent with Identifier.isValid. |
| // TODO(laurentlb): Handle Unicode letters. |
| int oldPos = pos - 1; |
| while (pos < buffer.length) { |
| switch (buffer[pos]) { |
| case '_': |
| case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': |
| case 'g': case 'h': case 'i': case 'j': case 'k': case 'l': |
| case 'm': case 'n': case 'o': case 'p': case 'q': case 'r': |
| case 's': case 't': case 'u': case 'v': case 'w': case 'x': |
| case 'y': case 'z': |
| case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': |
| case 'G': case 'H': case 'I': case 'J': case 'K': case 'L': |
| case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R': |
| case 'S': case 'T': case 'U': case 'V': case 'W': case 'X': |
| case 'Y': case 'Z': |
| case '0': case '1': case '2': case '3': case '4': case '5': |
| case '6': case '7': case '8': case '9': |
| pos++; |
| break; |
| default: |
| return bufferSlice(oldPos, pos); |
| } |
| } |
| return bufferSlice(oldPos, pos); |
| } |
| |
| /** |
| * Tokenizes a two-char operator. |
| * @return true if it tokenized an operator |
| */ |
| private boolean tokenizeTwoChars() { |
| if (pos + 2 >= buffer.length) { |
| return false; |
| } |
| char c1 = buffer[pos]; |
| char c2 = buffer[pos + 1]; |
| TokenKind tok = null; |
| if (c2 == '=') { |
| tok = EQUAL_TOKENS.get(c1); |
| } else if (c2 == '*' && c1 == '*') { |
| tok = TokenKind.STAR_STAR; |
| } |
| if (tok == null) { |
| return false; |
| } else { |
| setToken(tok, pos, pos + 2); |
| return true; |
| } |
| } |
| |
| // Returns the ith unconsumed char, or -1 for EOF. |
| private int peek(int i) { |
| return pos + i < buffer.length ? buffer[pos + i] : -1; |
| } |
| |
| // Consumes a char and returns the next unconsumed char, or -1 for EOF. |
| private int next() { |
| pos++; |
| return peek(0); |
| } |
| |
| /** |
| * Performs tokenization of the character buffer of file contents provided to the constructor. At |
| * least one token will be added to the tokens queue. |
| */ |
| private void tokenize() { |
| if (checkIndentation) { |
| checkIndentation = false; |
| computeIndentation(); |
| } |
| |
| // Return saved indentation tokens. |
| if (dents != 0) { |
| if (dents < 0) { |
| dents++; |
| setToken(TokenKind.OUTDENT, pos - 1, pos); |
| } else { |
| dents--; |
| setToken(TokenKind.INDENT, pos - 1, pos); |
| } |
| return; |
| } |
| |
| // TODO(adonovan): cleanup: replace break after setToken with return, |
| // and eliminate null-check of this.kind. |
| kind = null; |
| while (pos < buffer.length) { |
| if (tokenizeTwoChars()) { |
| pos += 2; |
| return; |
| } |
| char c = buffer[pos]; |
| pos++; |
| switch (c) { |
| case '{': |
| setToken(TokenKind.LBRACE, pos - 1, pos); |
| openParenStackDepth++; |
| break; |
| case '}': |
| setToken(TokenKind.RBRACE, pos - 1, pos); |
| popParen(); |
| break; |
| case '(': |
| setToken(TokenKind.LPAREN, pos - 1, pos); |
| openParenStackDepth++; |
| break; |
| case ')': |
| setToken(TokenKind.RPAREN, pos - 1, pos); |
| popParen(); |
| break; |
| case '[': |
| setToken(TokenKind.LBRACKET, pos - 1, pos); |
| openParenStackDepth++; |
| break; |
| case ']': |
| setToken(TokenKind.RBRACKET, pos - 1, pos); |
| popParen(); |
| break; |
| case '>': |
| if (peek(0) == '>' && peek(1) == '=') { |
| setToken(TokenKind.GREATER_GREATER_EQUALS, pos - 1, pos + 2); |
| pos += 2; |
| } else if (peek(0) == '>') { |
| setToken(TokenKind.GREATER_GREATER, pos - 1, pos + 1); |
| pos += 1; |
| } else { |
| setToken(TokenKind.GREATER, pos - 1, pos); |
| } |
| break; |
| case '<': |
| if (peek(0) == '<' && peek(1) == '=') { |
| setToken(TokenKind.LESS_LESS_EQUALS, pos - 1, pos + 2); |
| pos += 2; |
| } else if (peek(0) == '<') { |
| setToken(TokenKind.LESS_LESS, pos - 1, pos + 1); |
| pos += 1; |
| } else { |
| setToken(TokenKind.LESS, pos - 1, pos); |
| } |
| break; |
| case ':': |
| setToken(TokenKind.COLON, pos - 1, pos); |
| break; |
| case ',': |
| setToken(TokenKind.COMMA, pos - 1, pos); |
| break; |
| case '+': |
| setToken(TokenKind.PLUS, pos - 1, pos); |
| break; |
| case '-': |
| setToken(TokenKind.MINUS, pos - 1, pos); |
| break; |
| case '|': |
| setToken(TokenKind.PIPE, pos - 1, pos); |
| break; |
| case '=': |
| setToken(TokenKind.EQUALS, pos - 1, pos); |
| break; |
| case '%': |
| setToken(TokenKind.PERCENT, pos - 1, pos); |
| break; |
| case '~': |
| setToken(TokenKind.TILDE, pos - 1, pos); |
| break; |
| case '&': |
| setToken(TokenKind.AMPERSAND, pos - 1, pos); |
| break; |
| case '^': |
| setToken(TokenKind.CARET, pos - 1, pos); |
| break; |
| case '/': |
| if (peek(0) == '/' && peek(1) == '=') { |
| setToken(TokenKind.SLASH_SLASH_EQUALS, pos - 1, pos + 2); |
| pos += 2; |
| } else if (peek(0) == '/') { |
| setToken(TokenKind.SLASH_SLASH, pos - 1, pos + 1); |
| pos += 1; |
| } else { |
| // /= is handled by tokenizeTwoChars. |
| setToken(TokenKind.SLASH, pos - 1, pos); |
| } |
| break; |
| case ';': |
| setToken(TokenKind.SEMI, pos - 1, pos); |
| break; |
| case '*': |
| setToken(TokenKind.STAR, pos - 1, pos); |
| break; |
| case ' ': |
| case '\t': |
| case '\r': |
| /* ignore */ |
| break; |
| case '\\': |
| // Backslash character is valid only at the end of a line (or in a string) |
| if (peek(0) == '\n') { |
| pos += 1; // skip the end of line character |
| } else if (peek(0) == '\r' && peek(1) == '\n') { |
| pos += 2; // skip the CRLF at the end of line |
| } else { |
| setToken(TokenKind.ILLEGAL, pos - 1, pos); |
| setValue(Character.toString(c)); |
| } |
| break; |
| case '\n': |
| newline(); |
| break; |
| case '#': |
| int oldPos = pos - 1; |
| while (pos < buffer.length) { |
| c = buffer[pos]; |
| if (c == '\n') { |
| break; |
| } else { |
| pos++; |
| } |
| } |
| addComment(oldPos, pos); |
| break; |
| case '\'': |
| case '\"': |
| stringLiteral(c, false); |
| break; |
| default: |
| // detect raw strings, e.g. r"str" |
| if (c == 'r') { |
| int c0 = peek(0); |
| if (c0 == '\'' || c0 == '\"') { |
| pos++; |
| stringLiteral((char) c0, true); |
| break; |
| } |
| } |
| |
| // int or float literal, or dot |
| if (c == '.' || isdigit(c)) { |
| pos--; // unconsume |
| scanNumberOrDot(c); |
| break; |
| } |
| |
| if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_') { |
| identifierOrKeyword(); |
| } else { |
| error("invalid character: '" + c + "'", pos - 1); |
| } |
| break; |
| } // switch |
| if (kind != null) { // stop here if we scanned a token |
| return; |
| } |
| } // while |
| |
| if (indentStack.size() > 1) { // top of stack is always zero |
| setToken(TokenKind.NEWLINE, pos - 1, pos); |
| while (indentStack.size() > 1) { |
| indentStack.pop(); |
| dents--; |
| } |
| return; |
| } |
| |
| setToken(TokenKind.EOF, pos, pos); |
| } |
| |
| // Scans a number (INT or FLOAT) or DOT. |
| // Precondition: c == peek(0) (a dot or digit) |
| // |
| // TODO(adonovan): make this the precondition for all scan functions; |
| // currenly most assume their argument c has been consumed already. |
| private void scanNumberOrDot(int c) { |
| int start = this.pos; |
| boolean fraction = false; |
| boolean exponent = false; |
| |
| if (c == '.') { |
| // dot or start of fraction |
| if (!isdigit(peek(1))) { |
| pos++; // consume '.' |
| setToken(TokenKind.DOT, start, pos); |
| return; |
| } |
| fraction = true; |
| |
| } else if (c == '0') { |
| // hex, octal, binary or float |
| c = next(); |
| if (c == '.') { |
| fraction = true; |
| |
| } else if (c == 'x' || c == 'X') { |
| // hex |
| c = next(); |
| if (!isxdigit(c)) { |
| error("invalid hex literal", start); |
| } |
| while (isxdigit(c)) { |
| c = next(); |
| } |
| |
| } else if (c == 'o' || c == 'O') { |
| // octal |
| c = next(); |
| while (isdigit(c)) { |
| c = next(); |
| } |
| |
| } else if (c == 'b' || c == 'B') { |
| // binary |
| c = next(); |
| if (!isbdigit(c)) { |
| error("invalid binary literal", start); |
| } |
| while (isbdigit(c)) { |
| c = next(); |
| } |
| |
| } else { |
| // "0" or float or obsolete octal "0755" |
| while (isdigit(c)) { |
| c = next(); |
| } |
| if (c == '.') { |
| fraction = true; |
| } else if (c == 'e' || c == 'E') { |
| exponent = true; |
| } |
| } |
| |
| } else { |
| // decimal |
| while (isdigit(c)) { |
| c = next(); |
| } |
| if (c == '.') { |
| fraction = true; |
| } else if (c == 'e' || c == 'E') { |
| exponent = true; |
| } |
| } |
| |
| if (fraction) { |
| c = next(); // consume '.' |
| while (isdigit(c)) { |
| c = next(); |
| } |
| |
| if (c == 'e' || c == 'E') { |
| exponent = true; |
| } |
| } |
| |
| if (exponent) { |
| c = next(); // consume [eE] |
| if (c == '+' || c == '-') { |
| c = next(); |
| } |
| while (isdigit(c)) { |
| c = next(); |
| } |
| } |
| |
| // float? |
| if (fraction || exponent) { |
| setToken(TokenKind.FLOAT, start, pos); |
| double value = 0.0; |
| try { |
| value = Double.parseDouble(bufferSlice(start, pos)); |
| if (!Double.isFinite(value)) { |
| error("floating-point literal too large", start); |
| } |
| } catch (NumberFormatException ex) { |
| error("invalid float literal", start); |
| } |
| setValue(value); |
| return; |
| } |
| |
| // int |
| setToken(TokenKind.INT, start, pos); |
| String literal = bufferSlice(start, pos); |
| Number value = 0; |
| try { |
| value = IntLiteral.scan(literal); |
| } catch (NumberFormatException ex) { |
| error(ex.getMessage(), start); |
| } |
| setValue(value); |
| } |
| |
| private static boolean isdigit(int c) { |
| return '0' <= c && c <= '9'; |
| } |
| |
| private static boolean isxdigit(int c) { |
| return isdigit(c) || ('A' <= c && c <= 'F') || ('a' <= c && c <= 'f'); |
| } |
| |
| private static boolean isbdigit(int c) { |
| return c == '0' || c == '1'; |
| } |
| |
| /** |
| * Returns parts of the source buffer based on offsets |
| * |
| * @param start the beginning offset for the slice |
| * @param end the offset immediately following the slice |
| * @return the text at offset start with length end - start |
| */ |
| String bufferSlice(int start, int end) { |
| return new String(this.buffer, start, end - start); |
| } |
| |
| // TODO(adonovan): don't retain comments unconditionally. |
| private void addComment(int start, int end) { |
| String content = bufferSlice(start, end); |
| comments.add(new Comment(locs, start, content)); |
| } |
| } |
