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ChocoPy/src/main/cup/chocopy/pa1/ChocoPy.cup

284 lines
9.5 KiB

4 years ago
import java.util.ArrayList;
import java.util.List;
import java_cup.runtime.*;
import chocopy.common.astnodes.*;
/* The following code section is copied verbatim to the generated
* parser class. */
parser code {:
/* The following fields and methods deal with error reporting
* Avoid changing these unless you know what you are doing. */
/** Node that accumulates error messages to be added to the Program
* node produced as a result. */
public final Errors errors = new Errors(new ArrayList<>());
/** Return the Program node that results from parsing the stream of
* tokens produced by lexical analysis. In the case of syntax errors,
* the program may be empty, but will have error messages. */
public Program parseProgram(boolean debug) {
try {
Symbol result = debug ? debug_parse() : parse();
if (result == null || !(result.value instanceof Program)) {
return new Program(new Location(0, 0), new Location(0, 0),
new ArrayList<Declaration>(),
new ArrayList<Stmt>(),
errors);
} else {
return (Program) result.value;
}
} catch (RuntimeException excp) {
throw excp;
} catch (Exception excp) {
String msg =
String.format("Internal parser error detected: %s%n", excp);
throw new AssertionError(msg);
}
}
@Override
public SymbolFactory getSymbolFactory() {
return ((ChocoPyLexer) getScanner()).symbolFactory;
}
@Override
public void syntax_error(Symbol cur_token) {
String token = symbl_name_from_id(cur_token.sym);
String text = ((ChocoPyLexer) getScanner()).yytext();
errors.syntaxError(
((ComplexSymbolFactory.ComplexSymbol) cur_token).xleft,
((ComplexSymbolFactory.ComplexSymbol) cur_token).xright,
"Parse error near token %s: %s", token, text);
}
@Override
public void unrecovered_syntax_error(Symbol cur_token) {
/* Do not die */
}
:}
/**************************************************************************
* FEEL FREE TO MODIFY ANYTHING BELOW THIS LINE
*
* The rules provided below parse expressions of the form <INT> + <INT> + ...
* You can re-use these rules or edit them as you wish. The start rule
* should return a node of type Program.
*
* Tips: Production rules are usually followed by action code that will be
* copied to the generated parser to be executed immediately after a reduce
* operation; that is, when a production rule has been matched. You can name
* a nonterminal or terminal symbol in a production rule using the colon
* notation, e.g. expr_stmt ::= expr:e, to get the AST node for the matched
* expression. In the action code, `e` will be a variable of whatever type
* has been declared for the corresponding nonterminal, such as `Expr`.
* Therefore, you can construct an AST Node of type `ExprStmt` with `e` in the
* constructor: `new ExprStmt(exleft, exright, e)`
*
* The variables `exleft` and `exright` are automatically generated by CUP
* and contain Location objects for the start and end of the expression `e`.
* You can collect start and line number info for AST nodes by taking the
* location of the left end of the leftmost symbol in a rule and the
* location of the right end of the rightmost symbol. The auto-generated
* variables have names `<sym>xleft` and `<sym>xright`, where <sym> is the
* name given to the symbol using the colon notation.
*
* When you have nonterminals that are lists of things, e.g. List<Stmt> or
* List<Declaration>, it is helpful to get the leftmost and rightmost
* source location from within this list; we have provided some utility
* functions below to do just that.
**************************************************************************/
/* The following code section is copied verbatim to the class that performs
* production-rule actions. */
action code {:
/** Return a mutable list initially containing the single value ITEM. */
<T> List<T> single(T item) {
List<T> list = new ArrayList<>();
if (item != null) {
list.add(item);
}
return list;
}
/** If ITEM is non-null, appends it to the end of LIST. Then returns
* LIST. */
<T> List<T> combine(List<T> list, T item) {
if (item != null) {
list.add(item);
}
return list;
}
/** Return a mutable empty list. */
<T> List<T> empty() {
return new ArrayList<T>();
}
/** Return the leftmost non-whitespace location in NODES, or null if NODES
* is empty. Assumes that the nodes of NODES are ordered in increasing
* order of location, from left to right. */
ComplexSymbolFactory.Location getLeft(List<? extends Node> nodes) {
if (nodes.isEmpty()) {
return null;
}
Node first = nodes.get(0);
return new ComplexSymbolFactory.Location(first.getLocation()[0],
first.getLocation()[1]);
}
:}
/* Terminal symbols (tokens returned by the lexer). The declaration
* terminal <identifier1>, <identifier2>, ...;
* declares each <identifieri> as the denotation of a distinct type terminal
* symbol for use in the grammar. The declaration
* terminal <type> <identifier1>, ...;
* does the same, and in addition indicates that the lexer supplies a
* semantic value of type <type> for these symbols that may be referenced
* in actions ( {: ... :} ).
*/
terminal INDENT;
terminal DEDENT;
terminal String ID;
terminal String STRING;
/* Terminal Delimiters */
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terminal NEWLINE;
terminal String COLON;
terminal String COMMA;
/* Terminal Literals */
terminal Integer NUMBER;
terminal Boolean BOOL;
terminal String NONE;
/* Terminal Keywords */
terminal String IF;
terminal String ELSE;
terminal String ELIF;
terminal String WHILE;
terminal String CLASS;
terminal String DEF;
terminal String LAMBDA;
terminal String AS;
terminal String FOR;
terminal String GLOBAL;
terminal String IN;
terminal String NONLOCAL;
terminal String PASS;
terminal String RETURN;
terminal String ASSERT;
terminal String AWAIT;
terminal String BREAK;
terminal String CONTINUE;
terminal String DEL;
terminal String EXCEPT;
terminal String FINALLY;
terminal String FROM;
terminal String IMPORT;
terminal String RAISE;
terminal String TRY;
terminal String WITH;
terminal String YIELD;
/* Terminal Operators */
terminal String PLUS;
terminal String MINUS;
terminal String MUL;
terminal String DIV;
terminal String MOD;
terminal String GT;
terminal String LT;
terminal String EQUAL;
terminal String NEQ;
terminal String GEQ;
terminal String LEQ;
terminal String ASSIGN;
terminal String AND;
terminal String OR;
terminal String NOT;
terminal String DOT;
terminal String LPAR;
terminal String RPAR;
terminal String LBR;
terminal String RBR;
terminal String ARROW;
terminal String IS;
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/* Returned by the lexer for erroneous tokens. Since it does not appear in
* the grammar, it indicates a syntax error. */
terminal UNRECOGNIZED;
/* Nonterminal symbols (defined in production rules below).
* As for terminal symbols,
* non terminal <type> <identifier1>, ..., <identifiern>;
* defines the listed nonterminal identifier symbols to have semantic values
* of type <type>. */
non terminal Program program;
non terminal List<Declaration> program_head;
non terminal List<Stmt> stmt_list, opt_stmt_list;
non terminal Stmt stmt, expr_stmt;
non terminal Expr expr, binary_expr;
/* Precedences (lowest to highest) for resolving what would otherwise be
* ambiguities in the form of shift/reduce conflicts.. */
precedence left PLUS;
/* The start symbol. */
start with program;
/***** GRAMMAR RULES *****/
program ::= program_head:d opt_stmt_list:s
{: RESULT = new Program(d.isEmpty() ? getLeft(s) : getLeft(d),
sxright, d, s, errors);
:}
;
/* Initial list of declarations. */
program_head ::= /* not implemented; currently matches empty string */
{: RESULT = empty(); :}
;
opt_stmt_list ::= {: RESULT = empty(); :}
| stmt_list:s {: RESULT = s; :}
;
stmt_list ::= stmt:s {: RESULT = single(s); :}
| stmt_list:l stmt:s {: RESULT = combine(l, s); :}
| stmt_list:l error {: RESULT = l; :}
/* If there is a syntax error in the source, this says to discard
* symbols from the parsing stack and perform reductions until
* there is a stmt_list on top of the stack, and then to discard
* input symbols until it is possible to shift again, reporting
* a syntax error. */
;
stmt ::= expr_stmt:s NEWLINE {: RESULT = s; :}
;
expr_stmt ::= expr:e {: RESULT = new ExprStmt(exleft, exright, e); :}
;
expr ::= binary_expr:e {: RESULT = e; :}
| NUMBER:n {: RESULT = new IntegerLiteral(nxleft, nxright, n); :}
;
/* A binary expression, illustrating how to find the left and right
* source position of a phrase. */
binary_expr ::= expr:e1 PLUS:op expr:e2
{: RESULT = new BinaryExpr(e1xleft, e2xright,
e1, op, e2); :}
;