Started to Implement the Parser

2014-09-06 01:54:15 +02:00
parent 6aafbf9d2e
commit 8df8317413
10 changed files with 570 additions and 16 deletions
--- a/MathPad/MPMath.ym
+++ b/MathPad/MPMath.ym
@@ -0,0 +1,126 @@
+%{
+    #import "MPMath.h"
+    #define AT @
+    
+    MPParsedElement *parseResult;
+    
+    int yylex();
+    int yyparse();
+    FILE *yyin;
+    
+    void yyerror(const char *s);
+%}
+
+%error-verbose
+
+%initial-action
+{
+    parseResult = [[MPParsedElement alloc] init];
+};
+
+%union {
+	double number;
+}
+    /* Terminals */
+%token PLUS
+%left MINUS
+%token DOT
+%token <number> NUMBER
+
+    /* Nonterminals */
+%type <number> summands
+%type <number> factor
+%type <number> product
+
+%%
+
+element:
+        factor                   { parseResult.isFactor = YES;
+                                   parseResult.factor = $1;
+                                 }
+        | operator
+        | prefix summands suffix
+        ;
+
+factor:
+        DOT product DOT { $$ = $2;
+                        }
+        | DOT product   { $$ = $2;
+                        }
+        | product DOT   { $$ = $1;
+                        }
+        | product       { $$ = $1;
+                        }
+        ;
+
+product:
+        product DOT product { $$ = $1 * $3;
+                            }
+        | product product   { $$ = $1 * $2;
+                            }
+        | NUMBER            { $$ = $1;
+                            }
+        ;
+
+operator:
+        PLUS    { parseResult.suffixMultiplicator = 1;
+                  parseResult.hasSuffixMultiplicator = YES;
+                }
+        | MINUS { parseResult.suffixMultiplicator = -1;
+                  parseResult.hasSuffixMultiplicator = YES;
+                  NSLog(AT"Op");
+                }
+        | DOT   { parseResult.isFactor = YES;
+                  parseResult.factor = 1;
+                }
+        |       { parseResult.isFactor = YES;
+                  parseResult.factor = 1;
+                }
+        ;
+
+prefix:
+        DOT product { parseResult.prefixMultiplicator = $2;
+                      parseResult.hasPrefixMultiplicator = YES;
+                      parseResult.prefixOperatorExplicit = YES;
+                    }
+        | product   { parseResult.prefixMultiplicator = $1;
+                      parseResult.hasPrefixMultiplicator = YES;
+                      parseResult.prefixOperatorExplicit = YES;
+                    }
+        |           { parseResult.hasPrefixMultiplicator = NO;
+                    }
+        ;
+
+summands:
+        summands summand
+        | summand
+        ;
+
+summand:
+        PLUS product    { [parseResult.summands addObject:AT($2)];
+                        }
+        | MINUS product { [parseResult.summands addObject:AT(-$2)];
+                        }
+        ;
+
+suffix:
+        PLUS    { parseResult.suffixMultiplicator = 1;
+                  parseResult.hasSuffixMultiplicator = YES;
+                }
+        | MINUS { parseResult.suffixMultiplicator = -1;
+                  parseResult.hasSuffixMultiplicator = YES;
+                }
+        | DOT   { parseResult.suffixMultiplicator = 0;
+                  parseResult.hasSuffixMultiplicator = YES;
+                }
+        |       { parseResult.hasSuffixMultiplicator = NO;
+                }
+        ;
+
+%%
+
+void yyerror(const char *s) {
+    NSLog(@"EEK, parse error!  Message: %s", s);
+	// might as well halt now:
+	exit(-1);
+}