jgs Compilers Lecture 23: Semantic Analysis III Dr. Javier Gonzalez-Sanchez [email protected] 

jgs Previously … 

Dr. Javier Gonzalez-Sanchez | Compilers | 3 jgs Semantic Analysis 1. Declaration and Unicity. Review for uniqueness and that the variable has been declared before its usage. 2. Types. Review that the types of variables match the values assigned to them. 3. Array’s indexes. Review that the indexes are integers. 4. Conditions. Review that all expressions on the conditons return a boolean value. 5. Return type. Review that the value returned by a method match the type of the method. 6. Parameters. Review that the parameters in a method match in type and number with the declaration of the method. 

Dr. Javier Gonzalez-Sanchez | Compilers | 4 jgs 3. Conditions 

Dr. Javier Gonzalez-Sanchez | Compilers | 5 jgs Error Recovery PROGRAM BODY ASSIGNMENT VARIABLE WHILE IF RETURN PRINT C EXPRESSION X Y R E A B 

Dr. Javier Gonzalez-Sanchez | Compilers | 6 jgs Example { int a; int b; boolean c; a = 4; b = a + 1; if (a > b) { print (a); } } cube for matching types symbol table stack 

Dr. Javier Gonzalez-Sanchez | Compilers | 7 jgs Grammar → '{' '}’ → {';'|';'|';’|||';'} → identifier '=' → ('int'|'float'|'boolean'|'char’|'string'|'void')identifier → 'while' '(' ')' → 'if' '(' ')' ['else' ] → 'return' → ’print’ ‘(‘ ‘)’ → {'|' } → {'&' } → ['!'] → {('>'|'<'|'=='|'!=') } → {(’+'|'-’) } → {('*'|'/') } → ['-'] → integer | octal | hexadecimal | binary | true | false | string | char | float | identifier|'(' ')' 

Dr. Javier Gonzalez-Sanchez | Compilers | 8 jgs Conditions WHILE String x = SemanticAnalizer.popStack(); if (!x.equals(“boolean”) { error(3); } 

Dr. Javier Gonzalez-Sanchez | Compilers | 9 jgs Conditions IF String x = SemanticAnalizer.popStack(); if (!x.equals(“boolean”) { error(3); } 

Dr. Javier Gonzalez-Sanchez | Compilers | 10 jgs Semantic Analysis Declaration and Unicity. Review for uniqueness and that the variable has been declared before its usage. Type Matching. Review that the types of variables match the values assigned to them. Array’s indexes. Review that the indexes are integers. Conditions. Review that all expressions on the conditions return a boolean value. Return type. Review that the value returned by a method matches the type of the method. Parameters. Review that the parameters in a method match in type and number with the declaration of the method. 

Dr. Javier Gonzalez-Sanchez | Compilers | 11 jgs 4. Return Type 5. Parameters 

Dr. Javier Gonzalez-Sanchez | Compilers | 12 jgs Let’s Work 

jgs Notes 

Dr. Javier Gonzalez-Sanchez | Compilers | 19 jgs Addition 

Dr. Javier Gonzalez-Sanchez | Compilers | 20 jgs Logic Operators 

Dr. Javier Gonzalez-Sanchez | Compilers | 21 jgs Note 

Dr. Javier Gonzalez-Sanchez | Compilers | 22 jgs Let Us Work 1. Functions: Grammar and Semantic Validation 2. Arrays: Grammar and Semantic Validation 3. Switch, For, and Do/While: Grammar and Semantic Validation 4. CallToMethod: Grammar and Semantic Validation 

jgs Example 

Dr. Javier Gonzalez-Sanchez | Compilers | 24 jgs Test Case 1 1.{ 2.boolean boo; boolean foo; 3.int boo; int j; 4.int i; int minusfour; int k; 5.boolean k; 6.i = 4; 7.j = 3; 8.minusfour = boo; 9.while(i > 0) { 10. j = hello + 100 / 50; 11. while( j > 0) { 12. k = i*j; 13. print (k); 14. j = j-1; 15. } 16. i = i-1; 17.} 18.if (boo + minusfour) { 19. print (i); 20.} 21. 22.if (i < minusfour) { 23. print (j); 24.} 25.while (!i > minusfour) { 26. print (i); 27. i = i - 1; 28.} 29. 30.i = i + foo; 31.j = j + 1; 32.print (i); 33.print (j); 34.j = 100 > 90; 35.} 

Dr. Javier Gonzalez-Sanchez | Compilers | 25 jgs Test Case 1 1.Line 2: variable is already defined 2.Line 4: variable is already defined 3.Line 8: incompatible types: type mismatch 4.Line 10: variable not found 5.Line 10: incompatible types: type mismatch 6.Line 18: boolean expression expected 7.Line 30: incompatible types: type mismatch 8.Line 34: incompatible types: type mismatch 

Dr. Javier Gonzalez-Sanchez | Compilers | 26 jgs Questions 

jgs Compilers Javier Gonzalez-Sanchez, Ph.D. [email protected] Spring 2025 Copyright. These slides can only be used as study material for the Compilers course at Universidad Panamericana. They cannot be distributed or used for another purpose.