From 0f6565687e03968abd2e508fa8183f50f04f1cc7 Mon Sep 17 00:00:00 2001 From: bjculkin Date: Fri, 24 Mar 2017 16:21:07 -0400 Subject: Update Pratt Parser --- .../bjc/utils/parserutils/pratt/PrattParser.java | 83 ++++++++++++++-------- 1 file changed, 52 insertions(+), 31 deletions(-) (limited to 'BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/PrattParser.java') diff --git a/BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/PrattParser.java b/BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/PrattParser.java index a8c273d..e8543dc 100644 --- a/BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/PrattParser.java +++ b/BJC-Utils2/src/main/java/bjc/utils/parserutils/pratt/PrattParser.java @@ -3,6 +3,8 @@ package bjc.utils.parserutils.pratt; import bjc.utils.data.ITree; import bjc.utils.funcutils.NumberUtils; import bjc.utils.parserutils.ParserException; +import bjc.utils.parserutils.pratt.commands.DefaultNonInitialCommand; +import bjc.utils.parserutils.pratt.commands.DefaultInitialCommand; import java.util.HashMap; import java.util.Map; @@ -13,29 +15,29 @@ import java.util.Map; * @author EVE * * @param - * The key type for the tokens. + * The key type for the tokens. * * @param - * The value type for the tokens. + * The value type for the tokens. * * @param - * The state type of the parser. + * The state type of the parser. * * */ public class PrattParser { - private final LeftCommand DEFAULT_LEFT_COMMAND = new DefaultLeftCommand<>(); - private final NullCommand DEFAULT_NULL_COMMAND = new DefaultNullCommand<>(); + private final NonInitialCommand DEFAULT_LEFT_COMMAND = new DefaultNonInitialCommand<>(); + private final InitialCommand DEFAULT_NULL_COMMAND = new DefaultInitialCommand<>(); - private Map> leftCommands; - private Map> nullCommands; - private Map> statementCommands; + private Map> leftCommands; + private Map> nullCommands; + private Map> statementCommands; /** * Create a new Pratt parser. * * @param terminal - * The terminal symbol. + * The terminal symbol. */ public PrattParser() { leftCommands = new HashMap<>(); @@ -47,22 +49,25 @@ public class PrattParser { * Parse an expression. * * @param precedence - * The initial precedence for the expression. + * The initial precedence for the expression. * * @param tokens - * The tokens for the expression. + * The tokens for the expression. * * @param state - * The state of the parser. + * The state of the parser. + * + * @param isStatement + * Whether or not to parse statements. * * @return The expression as an AST. * * @throws ParserException - * If something goes wrong during parsing. + * If something goes wrong during parsing. */ - public ITree> parseExpression(int precedence, TokenStream tokens, C state, boolean isStatement) - throws ParserException { - if (precedence < 0) { + public ITree> parseExpression(int precedence, TokenStream tokens, C state, + boolean isStatement) throws ParserException { + if(precedence < 0) { throw new IllegalArgumentException("Precedence must be greater than zero"); } @@ -71,28 +76,28 @@ public class PrattParser { ITree> ast; - if (isStatement && statementCommands.containsKey(initToken.getKey())) { - ast = statementCommands.getOrDefault(initToken.getKey(), DEFAULT_NULL_COMMAND).nullDenotation(initToken, - new ParserContext<>(tokens, this, state)); + if(isStatement && statementCommands.containsKey(initToken.getKey())) { + ast = statementCommands.getOrDefault(initToken.getKey(), DEFAULT_NULL_COMMAND) + .denote(initToken, new ParserContext<>(tokens, this, state)); } else { - ast = nullCommands.getOrDefault(initToken.getKey(), DEFAULT_NULL_COMMAND).nullDenotation(initToken, - new ParserContext<>(tokens, this, state)); + ast = nullCommands.getOrDefault(initToken.getKey(), DEFAULT_NULL_COMMAND) + .denote(initToken, new ParserContext<>(tokens, this, state)); } int rightPrec = Integer.MAX_VALUE; - while (true) { + while(true) { Token tok = tokens.current(); K key = tok.getKey(); - LeftCommand command = leftCommands.getOrDefault(key, DEFAULT_LEFT_COMMAND); + NonInitialCommand command = leftCommands.getOrDefault(key, DEFAULT_LEFT_COMMAND); int leftBind = command.leftBinding(); - if (NumberUtils.between(precedence, rightPrec, leftBind)) { + if(NumberUtils.between(precedence, rightPrec, leftBind)) { tokens.next(); - ast = command.leftDenote(ast, tok, new ParserContext<>(tokens, this, state)); + ast = command.denote(ast, tok, new ParserContext<>(tokens, this, state)); rightPrec = command.nextBinding(); } else { break; @@ -106,12 +111,12 @@ public class PrattParser { * Add a non-initial command to this parser. * * @param marker - * The key that marks the command. + * The key that marks the command. * * @param comm - * The command. + * The command. */ - public void addNonInitialCommand(K marker, LeftCommand comm) { + public void addNonInitialCommand(K marker, NonInitialCommand comm) { leftCommands.put(marker, comm); } @@ -119,12 +124,28 @@ public class PrattParser { * Add a initial command to this parser. * * @param marker - * The key that marks the command. + * The key that marks the command. * * @param comm - * The command. + * The command. */ - public void addInitialCommand(K marker, NullCommand comm) { + public void addInitialCommand(K marker, InitialCommand comm) { nullCommands.put(marker, comm); } + + /** + * Add a statement command to this parser. + * + * The difference between statements and initial commands is that + * statements can only appear at the start of the expression. + * + * @param marker + * The key that marks the command. + * + * @param comm + * The command. + */ + public void addStatementCommand(K marker, InitialCommand comm) { + statementCommands.put(marker, comm); + } } -- cgit v1.2.3