Static Semantics. Lecture 15. (Notes by P. N. Hilfinger and R. Bodik) 2/29/08 Prof. Hilfinger, CS164 Lecture 15 1
|
|
- Mitchell Dorsey
- 6 years ago
- Views:
Transcription
1 Static Semantics Lecture 15 (Notes by P. N. Hilfinger and R. Bodik) 2/29/08 Prof. Hilfinger, CS164 Lecture 15 1
2 Current Status Lexical analysis Produces tokens Detects & eliminates illegal tokens Parsing Produces trees Detects & eliminates ill-formed parse trees Static semantic analysis we are here Produces decorated tree with additional information attached Detects & eliminates remaining static errors 2/29/08 Prof. Hilfinger, CS164 Lecture 15 2
3 Static vs. Dynamic We use the term static to describe properties that the compiler can determine without considering any particular execution. E.g., in def f(x) : x + 1 Both uses of x refer to same variable Dynamic properties are those that depend on particular executions in general. E.g., will x = x/y cause an arithmetic exception. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 3
4 Static vs. Dynamic, contd. Actually, distinction is not that simple. E.g., after x = 3 y = x + 2 compiler could deduce that x and y are Ints But languages often designed to require that we treat variables only according to explicitly declared types, because deductions are difficult or impossible in general. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 4
5 Typical Tasks of the Semantic Analyzer Find the declaration that defines each identifier instance Determine the static types of expressions Perform re-organizations of the AST that were inconvenient in parser, or required semantic information Detect errors and fix to allow further processing 2/29/08 Prof. Hilfinger, CS164 Lecture 15 5
6 Typical Semantic Errors: Java, C++ Multiple declarations: a variable should be declared (in the same region) at most once Undeclared variable: a variable should not be used before being declared. Type mismatch: type of the left-hand side of an assignment should match the type of the right-hand side. Wrong arguments: methods should be called with the right number and types of arguments. Definite-assignment check (Java): conservative check that simple variables assigned to before use. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 6
7 Output from Static Semantic Analysis Input is AST; output is an annotated tree. x = 3 def f (x): return x+y y: Int y = 2 #1: x, Any, 0 #2: f, Any->Any, 0 #3: x, Any, 1 #4: y, Int, 0 x = def type_decl = 3 f return y Int y 2 #1 #2 Int 2/29/08 Prof. Hilfinger, CS164 Lecture 15 7 x #3 x + Any y #3 #4 #4 #4 Ids decorated with declarations. Expressions annotated with (static) types. Int
8 Output from Static Semantic Analysis (II) Analysis has added objects we ll call symbol entries to hold information about instances of identifiers. In this example, #1: x, Any, 0 denotes an entry for something named x occurring at the outer lexical level (level 0) and having static type Any. For other expressions, we annotate with static type information. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 8
9 Output from Static Semantic Analysis (III) Symbol entries for classes (or modules, packages, namespaces and the like) must contain equivalent of a dictionary mapping names of members to symbol entries. So given an expression such as x.clear (), we find symbol entry for x find type (class) of x from its entry, and find clear in dictionary of entry associated with x s type. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 9
10 Binding names to symbol entries: Scoping Scope of a declaration: section of text where it applies Declarative region: section of text that bounds scopes of declarations (we ll say region for short) In most languages, the same name can be declared multiple times if its declarations occur in different declarative regions, and/or involve different kinds of names. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 10
11 Scoping: example Java: can use same name for a class, field of the class, a method of the class, and a local variable of the method legal Java program: class Test { int Test; Test( ) { double Test; } } 2/29/08 Prof. Hilfinger, CS164 Lecture 15 11
12 Scoping: general rules The scope rules of a language: determine which declaration of a named object corresponds to each use of the object. Scoping rules map uses of objects to their declarations (or symbol entries). C++ and Java use static scoping: mapping from uses to declarations is made at compile time. C++ uses Algol scope rules a use of variable x matches the declaration with the most closely enclosing scope. a deeply nested variable x hides x declared in an outer region. in Java: inner regions cannot define variables defined in outer regions 2/29/08 Prof. Hilfinger, CS164 Lecture 15 12
13 Scoping Options: Declarative Regions In Java, each function has one or more declarative regions: one for the function body, and possibly additional regions in the function for each for loop and each nested block (delimited by curly braces) In Pyth, each function has one per function (possibly plus more for nested functions) 2/29/08 Prof. Hilfinger, CS164 Lecture 15 13
14 Example (assume C++ rules) double y, k; void f(int y) { y = k; int k = 0; while (k) { int k = 1; } } // y and k global variables // y also used as a parameter // Uses global k and parameter y // k is now local variable // refers to 2nd decl of k // another local var, in a loop (not ok in Java) global k hidden starting here the outermost region includes decls of "f, k and y function f itself has two (nested) regions: 1. The outer region for f includes parameter y and local variable k. 2. The innermost region is for the body of the while loop, and includes the variable k that is initialized to 1. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 14
15 Scoping Options: overloading Java and C++ (but not in Pascal, C, or Pyth): can use the same name for more than one method as long as the number and/or types of parameters are unique. int add(int a, int b); float add(float a, float b); 2/29/08 Prof. Hilfinger, CS164 Lecture 15 15
16 Scoping options: Use before declaration? Can names be used before they are defined? Java, C++: a method or field name can be used before the definition appears; not true for a variable, whose scope starts at its declaration In Pyth, almost anything can be used before declaration, where syntactically possible 2/29/08 Prof. Hilfinger, CS164 Lecture 15 16
17 Scoping Options: Dynamic scoping Not all languages use static scoping. Original Lisp, APL, and Snobol use dynamic scoping. Dynamic scoping: A use of a variable that has no corresponding declaration in the same function corresponds to the declaration in the most-recently-called still active function. With this rule, difficult for compiler to determine much about identifiers 2/29/08 Prof. Hilfinger, CS164 Lecture 15 17
18 Example For example, consider the following code: void main() { f1(); f2(); } void f1() { int x = 10; g(); } void f2() { String x = "hello"; f3();g(); } void f3() { double x = 30.5; } void g() { print(x); } With static scoping, illegal. With dynamic scoping, prints 10 and hello 2/29/08 Prof. Hilfinger, CS164 Lecture 15 18
19 So How do we Annotate with Declarations? Idea is to recursively navigate the AST, in effect executing the program in simplified fashion, extracting information that isn t data dependent. You saw it in CS61A (sort of). 2/29/08 Prof. Hilfinger, CS164 Lecture 15 19
20 Environment Diagrams and Symbol Entries In Scheme, a program like (set! x 7) (define (f x) (let ((y (+ x 39)) (+ x y))) (f 3) when executed would eventually give you something like this when computing (+ x y) X: 7 f: x: 3 y: 42 current environment global environment 2/29/08 Prof. Hilfinger, CS164 Lecture 15 20
21 Environment Diagrams to Symbol Entries Abstracting from this particular execution, X: 7 f: x: 3 y: 42 current environment we take away the values and replace with static info: #1. X: Any #2. f: Any->Any #3. x: Any #4. y: Any current environment and we re left with symbol entries and a data structure (a kind of symbol table) for looking them up. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 21
22 Annotating Pyth with Symbol Entries Process requires several passes (traversals of AST). A rough outline: 1. Create symbol entries for all classes and record in global environment, plus entries for all class members stored in the class s entries. 2. For each declarative region, A. Create a new environment box for each declaration immediately inside the region. B. Use it to annotate all uses, and recursively do step 2 for all inner declarative regions. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 22
23 Type Checking the job of the type-checking phase is to: Determine the type of each expression in the program (each node in the AST that corresponds to an expression) Find type errors The type rules of a language define how to determine expression types, and what is considered to be an error. The type rules specify, for every operator (including assignment), what types the operands can have, and what is the type of the result. 2/29/08 Prof. Hilfinger, CS164 Lecture 15 23
24 Type Errors The type checker must also 1. find type errors having to do with the context of expressions, e.g., the context of some operators must be boolean, 2. type errors having to do with method calls. Examples of the context errors: the condition of an if not boolean (Java) type of returned value not function s return type Examples of method errors: calling something that is not a method calling a method with the wrong number of arguments calling a method with arguments of the wrong types 2/29/08 Prof. Hilfinger, CS164 Lecture 15 24
Lecture 16: Static Semantics Overview 1
Lecture 16: Static Semantics Overview 1 Lexical analysis Produces tokens Detects & eliminates illegal tokens Parsing Produces trees Detects & eliminates ill-formed parse trees Static semantic analysis
More informationSyntax Errors; Static Semantics
Dealing with Syntax Errors Syntax Errors; Static Semantics Lecture 14 (from notes by R. Bodik) One purpose of the parser is to filter out errors that show up in parsing Later stages should not have to
More informationCS1622. Semantic Analysis. The Compiler So Far. Lecture 15 Semantic Analysis. How to build symbol tables How to use them to find
CS1622 Lecture 15 Semantic Analysis CS 1622 Lecture 15 1 Semantic Analysis How to build symbol tables How to use them to find multiply-declared and undeclared variables. How to perform type checking CS
More informationThe Compiler So Far. CSC 4181 Compiler Construction. Semantic Analysis. Beyond Syntax. Goals of a Semantic Analyzer.
The Compiler So Far CSC 4181 Compiler Construction Scanner - Lexical analysis Detects inputs with illegal tokens e.g.: main 5 (); Parser - Syntactic analysis Detects inputs with ill-formed parse trees
More information1 Terminology. 2 Environments and Static Scoping. P. N. Hilfinger. Fall Static Analysis: Scope and Types
and Computer Sciences Computer Science Division CS 164 Fall 2006 P. N. Hilfinger Static Analysis: Scope and Types 1 Terminology Programs, in general, are simply collections of definitions of terms, which
More informationLECTURE 14. Names, Scopes, and Bindings: Scopes
LECTURE 14 Names, Scopes, and Bindings: Scopes SCOPE The scope of a binding is the textual region of a program in which a name-to-object binding is active. Nonspecifically, scope is a program region of
More informationSemantic Analysis. Outline. The role of semantic analysis in a compiler. Scope. Types. Where we are. The Compiler so far
Outline Semantic Analysis The role of semantic analysis in a compiler A laundry list of tasks Scope Static vs. Dynamic scoping Implementation: symbol tables Types Statically vs. Dynamically typed languages
More informationInformal Semantics of Data. semantic specification names (identifiers) attributes binding declarations scope rules visibility
Informal Semantics of Data semantic specification names (identifiers) attributes binding declarations scope rules visibility 1 Ways to Specify Semantics Standards Documents (Language Definition) Language
More informationSemantic Analysis. Outline. The role of semantic analysis in a compiler. Scope. Types. Where we are. The Compiler Front-End
Outline Semantic Analysis The role of semantic analysis in a compiler A laundry list of tasks Scope Static vs. Dynamic scoping Implementation: symbol tables Types Static analyses that detect type errors
More informationThe role of semantic analysis in a compiler
Semantic Analysis Outline The role of semantic analysis in a compiler A laundry list of tasks Scope Static vs. Dynamic scoping Implementation: symbol tables Types Static analyses that detect type errors
More informationThe Compiler So Far. Lexical analysis Detects inputs with illegal tokens. Overview of Semantic Analysis
The Compiler So Far Overview of Semantic Analysis Adapted from Lectures by Profs. Alex Aiken and George Necula (UCB) Lexical analysis Detects inputs with illegal tokens Parsing Detects inputs with ill-formed
More information5. Semantic Analysis. Mircea Lungu Oscar Nierstrasz
5. Semantic Analysis Mircea Lungu Oscar Nierstrasz Thanks to Jens Palsberg and Tony Hosking for their kind permission to reuse and adapt the CS132 and CS502 lecture notes. http://www.cs.ucla.edu/~palsberg/
More information5. Semantic Analysis!
5. Semantic Analysis! Prof. O. Nierstrasz! Thanks to Jens Palsberg and Tony Hosking for their kind permission to reuse and adapt the CS132 and CS502 lecture notes.! http://www.cs.ucla.edu/~palsberg/! http://www.cs.purdue.edu/homes/hosking/!
More informationSEMANTIC ANALYSIS TYPES AND DECLARATIONS
SEMANTIC ANALYSIS CS 403: Type Checking Stefan D. Bruda Winter 2015 Parsing only verifies that the program consists of tokens arranged in a syntactically valid combination now we move to check whether
More informationSyntax-Directed Translation. Lecture 14
Syntax-Directed Translation Lecture 14 (adapted from slides by R. Bodik) 9/27/2006 Prof. Hilfinger, Lecture 14 1 Motivation: parser as a translator syntax-directed translation stream of tokens parser ASTs,
More information1 Lexical Considerations
Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6.035, Spring 2013 Handout Decaf Language Thursday, Feb 7 The project for the course is to write a compiler
More informationNames, Scope, and Bindings
Names, Scope, and Bindings COMS W4115 Prof. Stephen A. Edwards Fall 2007 Columbia University Department of Computer Science What s In a Name? Name: way to refer to something else variables, functions,
More informationUNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division. P. N. Hilfinger
UNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division CS 164 Spring 2005 P. N. Hilfinger Project #2: Static Analyzer for Pyth Due: Wednesday, 6 April
More informationUNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division. P. N. Hilfinger
UNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division CS 164 Spring 2018 P. N. Hilfinger Project #2: Static Analyzer Due: Friday, 6 April 2018 The
More informationCompiler construction
Compiler construction Martin Steffen March 13, 2017 Contents 1 Abstract 1 1.1 Symbol tables. 1 1.1.1 Introduction 1 1.1.2 Symbol table design and interface.. 2 1.1.3 Implementing symbol tables 3 1.1.4
More informationSemantic Analysis. Compiler Architecture
Processing Systems Prof. Mohamed Hamada Software Engineering Lab. The University of Aizu Japan Source Compiler Architecture Front End Scanner (lexical tokens Parser (syntax Parse tree Semantic Analysis
More informationAnatomy of a Compiler. Overview of Semantic Analysis. The Compiler So Far. Why a Separate Semantic Analysis?
Anatomy of a Compiler Program (character stream) Lexical Analyzer (Scanner) Syntax Analyzer (Parser) Semantic Analysis Parse Tree Intermediate Code Generator Intermediate Code Optimizer Code Generator
More informationLexical Considerations
Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6.035, Fall 2005 Handout 6 Decaf Language Wednesday, September 7 The project for the course is to write a
More informationSemantic Analysis and Type Checking
Semantic Analysis and Type Checking The compilation process is driven by the syntactic structure of the program as discovered by the parser Semantic routines: interpret meaning of the program based on
More informationTail Calls. CMSC 330: Organization of Programming Languages. Tail Recursion. Tail Recursion (cont d) Names and Binding. Tail Recursion (cont d)
CMSC 330: Organization of Programming Languages Tail Calls A tail call is a function call that is the last thing a function does before it returns let add x y = x + y let f z = add z z (* tail call *)
More informationNames, Scope, and Bindings
Names, Scope, and Bindings COMS W4115 Prof. Stephen A. Edwards Spring 2007 Columbia University Department of Computer Science What s In a Name? Name: way to refer to something else variables, functions,
More informationThe Structure of a Syntax-Directed Compiler
Source Program (Character Stream) Scanner Tokens Parser Abstract Syntax Tree Type Checker (AST) Decorated AST Translator Intermediate Representation Symbol Tables Optimizer (IR) IR Code Generator Target
More informationCS 330 Lecture 18. Symbol table. C scope rules. Declarations. Chapter 5 Louden Outline
CS 0 Lecture 8 Chapter 5 Louden Outline The symbol table Static scoping vs dynamic scoping Symbol table Dictionary associates names to attributes In general: hash tables, tree and lists (assignment ) can
More information5. Semantic Analysis. Mircea Lungu Oscar Nierstrasz
5. Semantic Analysis Mircea Lungu Oscar Nierstrasz Thanks to Jens Palsberg and Tony Hosking for their kind permission to reuse and adapt the CS132 and CS502 lecture notes. http://www.cs.ucla.edu/~palsberg/
More informationCSCE 314 Programming Languages. Type System
CSCE 314 Programming Languages Type System Dr. Hyunyoung Lee 1 Names Names refer to different kinds of entities in programs, such as variables, functions, classes, templates, modules,.... Names can be
More informationThe SPL Programming Language Reference Manual
The SPL Programming Language Reference Manual Leonidas Fegaras University of Texas at Arlington Arlington, TX 76019 fegaras@cse.uta.edu February 27, 2018 1 Introduction The SPL language is a Small Programming
More informationCSCI312 Principles of Programming Languages!
CSCI312 Principles of Programming Languages! Scope Xu Liu ! 4.1 Syntactic Issues! 4.2 Variables! 4.3 Scope! 4.4 Symbol Table! 4.5 Resolving References! 4.6 Dynamic Scoping! 4.7 Visibility! 4.8 Overloading!
More informationNames, Scope, and Bindings
Names, Scope, and Bindings COMS W4115 Prof. Stephen A. Edwards Fall 2003 Columbia University Department of Computer Science What s In a Name? Name: way to refer to something else variables, functions,
More informationEvery language has its own scoping rules. For example, what is the scope of variable j in this Java program?
Lexical Binding There are two ways a variable can be used in a program: As a declaration As a "reference" or use of the variable Scheme has two kinds of variable "declarations" -- the bindings of a let-expression
More informationThe compilation process is driven by the syntactic structure of the program as discovered by the parser
Semantic Analysis The compilation process is driven by the syntactic structure of the program as discovered by the parser Semantic routines: interpret meaning of the program based on its syntactic structure
More informationProf. Mohamed Hamada Software Engineering Lab. The University of Aizu Japan
Language Processing Systems Prof. Mohamed Hamada Software Engineering Lab. The University of Aizu Japan Semantic Analysis Compiler Architecture Front End Back End Source language Scanner (lexical analysis)
More informationLexical Considerations
Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science 6.035, Spring 2010 Handout Decaf Language Tuesday, Feb 2 The project for the course is to write a compiler
More informationCSE 307: Principles of Programming Languages
1 / 26 CSE 307: Principles of Programming Languages Names, Scopes, and Bindings R. Sekar 2 / 26 Topics Bindings 1. Bindings Bindings: Names and Attributes Names are a fundamental abstraction in languages
More informationTypes and Type Inference
CS 242 2012 Types and Type Inference Notes modified from John Mitchell and Kathleen Fisher Reading: Concepts in Programming Languages, Revised Chapter 6 - handout on Web!! Outline General discussion of
More information4 Bindings and Scope. Bindings and environments. Scope, block structure, and visibility. Declarations. Blocks. 2004, D.A. Watt, University of Glasgow
4 Bindings and Scope Bindings and environments. Scope, block structure, and visibility. Declarations. Blocks. 2004, D.A. Watt, University of Glasgow 1 Bindings and environments PL expressions and commands
More informationJavaScript: Sort of a Big Deal,
: Sort of a Big Deal, But Sort of Quirky... March 20, 2017 Lisp in C s Clothing (Crockford, 2001) Dynamically Typed: no static type annotations or type checks. C-Like Syntax: curly-braces, for, semicolons,
More informationLecture 7: Type Systems and Symbol Tables. CS 540 George Mason University
Lecture 7: Type Systems and Symbol Tables CS 540 George Mason University Static Analysis Compilers examine code to find semantic problems. Easy: undeclared variables, tag matching Difficult: preventing
More informationAcknowledgement. CS Compiler Design. Semantic Processing. Alternatives for semantic processing. Intro to Semantic Analysis. V.
Acknowledgement CS3300 - Compiler Design Intro to Semantic Analysis V. Krishna Nandivada IIT Madras Copyright c 2000 by Antony L. Hosking. Permission to make digital or hard copies of part or all of this
More informationCompilers. Type checking. Yannis Smaragdakis, U. Athens (original slides by Sam
Compilers Type checking Yannis Smaragdakis, U. Athens (original slides by Sam Guyer@Tufts) Summary of parsing Parsing A solid foundation: context-free grammars A simple parser: LL(1) A more powerful parser:
More informationTopics Covered Thus Far. CMSC 330: Organization of Programming Languages. Language Features Covered Thus Far. Programming Languages Revisited
CMSC 330: Organization of Programming Languages Type Systems, Names & Binding Topics Covered Thus Far Programming languages Syntax specification Regular expressions Context free grammars Implementation
More informationUNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division. P. N. Hilfinger
UNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division CS 164 Spring 2009 P. N. Hilfinger CS 164: Final Examination (corrected) Name: Login: You have
More informationStatic Semantics. Winter /3/ Hal Perkins & UW CSE I-1
CSE 401 Compilers Static Semantics Hal Perkins Winter 2009 2/3/2009 2002-09 Hal Perkins & UW CSE I-1 Agenda Static semantics Types Symbol tables General ideas for now; details later for MiniJava project
More informationDecaf Language Reference
Decaf Language Reference Mike Lam, James Madison University Fall 2016 1 Introduction Decaf is an imperative language similar to Java or C, but is greatly simplified compared to those languages. It will
More informationSymbol Table Information. Symbol Tables. Symbol table organization. Hash Tables. What kind of information might the compiler need?
Symbol Table Information For compile-time efficiency, compilers often use a symbol table: associates lexical names (symbols) with their attributes What items should be entered? variable names defined constants
More informationType Inference Systems. Type Judgments. Deriving a Type Judgment. Deriving a Judgment. Hypothetical Type Judgments CS412/CS413
Type Inference Systems CS412/CS413 Introduction to Compilers Tim Teitelbaum Type inference systems define types for all legal programs in a language Type inference systems are to type-checking: As regular
More informationCMSC 330: Organization of Programming Languages
CMSC 330: Organization of Programming Languages Type Systems, Names and Binding CMSC 330 - Spring 2013 1 Topics Covered Thus Far! Programming languages Ruby OCaml! Syntax specification Regular expressions
More informationCS558 Programming Languages
CS558 Programming Languages Fall 2017 Lecture 3a Andrew Tolmach Portland State University 1994-2017 Binding, Scope, Storage Part of being a high-level language is letting the programmer name things: variables
More informationTypescript on LLVM Language Reference Manual
Typescript on LLVM Language Reference Manual Ratheet Pandya UNI: rp2707 COMS 4115 H01 (CVN) 1. Introduction 2. Lexical Conventions 2.1 Tokens 2.2 Comments 2.3 Identifiers 2.4 Reserved Keywords 2.5 String
More informationSymbol Tables. For compile-time efficiency, compilers often use a symbol table: associates lexical names (symbols) with their attributes
For compile-time efficiency, compilers often use a symbol table: associates lexical names (symbols) with their attributes What items should be entered? variable names defined constants procedure and function
More informationWhen do We Run a Compiler?
When do We Run a Compiler? Prior to execution This is standard. We compile a program once, then use it repeatedly. At the start of each execution We can incorporate values known at the start of the run
More informationUNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division. P. N. Hilfinger
UNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division CS 164 Spring 2010 P. N. Hilfinger CS 164: Final Examination (revised) Name: Login: You have
More informationTime : 1 Hour Max Marks : 30
Total No. of Questions : 6 P4890 B.E/ Insem.- 74 B.E ( Computer Engg) PRINCIPLES OF MODERN COMPILER DESIGN (2012 Pattern) (Semester I) Time : 1 Hour Max Marks : 30 Q.1 a) Explain need of symbol table with
More informationTopics Covered Thus Far CMSC 330: Organization of Programming Languages
Topics Covered Thus Far CMSC 330: Organization of Programming Languages Names & Binding, Type Systems Programming languages Ruby Ocaml Lambda calculus Syntax specification Regular expressions Context free
More informationThe PCAT Programming Language Reference Manual
The PCAT Programming Language Reference Manual Andrew Tolmach and Jingke Li Dept. of Computer Science Portland State University September 27, 1995 (revised October 15, 2002) 1 Introduction The PCAT language
More informationLecture 09: Data Abstraction ++ Parsing is the process of translating a sequence of characters (a string) into an abstract syntax tree.
Lecture 09: Data Abstraction ++ Parsing Parsing is the process of translating a sequence of characters (a string) into an abstract syntax tree. program text Parser AST Processor Compilers (and some interpreters)
More informationScope. CSC 4181 Compiler Construction. Static Scope. Static Scope Rules. Closest Nested Scope Rule
Scope CSC 4181 Compiler Construction Scope and Symbol Table A scope is a textual region of the program in which a (name-to-object) binding is active. There are two types of scope: Static scope Dynamic
More informationCS558 Programming Languages
CS558 Programming Languages Winter 2017 Lecture 7b Andrew Tolmach Portland State University 1994-2017 Values and Types We divide the universe of values according to types A type is a set of values and
More informationLECTURE 3. Compiler Phases
LECTURE 3 Compiler Phases COMPILER PHASES Compilation of a program proceeds through a fixed series of phases. Each phase uses an (intermediate) form of the program produced by an earlier phase. Subsequent
More informationToday. Assignments. Lecture Notes CPSC 326 (Spring 2019) Quiz 5. Exam 1 overview. Type checking basics. HW4 due. HW5 out, due in 2 Tuesdays
Today Quiz 5 Exam 1 overview Type checking basics Assignments HW4 due HW5 out, due in 2 Tuesdays S. Bowers 1 of 11 Exam Overview Basics closed notes, book, etc. 4 multi-part questions worth 15% of final
More informationComputer Science Department Carlos III University of Madrid Leganés (Spain) David Griol Barres
Computer Science Department Carlos III University of Madrid Leganés (Spain) David Griol Barres dgriol@inf.uc3m.es Introduction He am a driver might be syntactically correct but semantically wrong. Semantic
More informationA Short Summary of Javali
A Short Summary of Javali October 15, 2015 1 Introduction Javali is a simple language based on ideas found in languages like C++ or Java. Its purpose is to serve as the source language for a simple compiler
More informationWriting Evaluators MIF08. Laure Gonnord
Writing Evaluators MIF08 Laure Gonnord Laure.Gonnord@univ-lyon1.fr Evaluators, what for? Outline 1 Evaluators, what for? 2 Implementation Laure Gonnord (Lyon1/FST) Writing Evaluators 2 / 21 Evaluators,
More informationIPCoreL. Phillip Duane Douglas, Jr. 11/3/2010
IPCoreL Programming Language Reference Manual Phillip Duane Douglas, Jr. 11/3/2010 The IPCoreL Programming Language Reference Manual provides concise information about the grammar, syntax, semantics, and
More information(Not Quite) Minijava
(Not Quite) Minijava CMCS22620, Spring 2004 April 5, 2004 1 Syntax program mainclass classdecl mainclass class identifier { public static void main ( String [] identifier ) block } classdecl class identifier
More informationUNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division
UNIVERSITY OF CALIFORNIA Department of Electrical Engineering and Computer Sciences Computer Science Division Fall, 2001 Prof. R. Fateman SUGGESTED S CS 164 Final Examination: December 18, 2001, 8-11AM
More informationType Bindings. Static Type Binding
Type Bindings Two key issues in binding (or associating) a type to an identifier: How is type binding specified? When does the type binding take place? N. Meng, S. Arthur 1 Static Type Binding An explicit
More informationVisitors. Move functionality
Visitors Compiler Construction Visitor pattern, Semantic analysis Lennart Andersson How to modularize in Java (or any other OO language) if we do not have access to AOP mechanisms? Revision 2011-02-08
More informationThe Structure of a Syntax-Directed Compiler
Source Program (Character Stream) Scanner Tokens Parser Abstract Syntax Tree (AST) Type Checker Decorated AST Translator Intermediate Representation Symbol Tables Optimizer (IR) IR Code Generator Target
More informationTypes and Type Inference
Types and Type Inference Mooly Sagiv Slides by Kathleen Fisher and John Mitchell Reading: Concepts in Programming Languages, Revised Chapter 6 - handout on the course homepage Outline General discussion
More informationTopic 6: Types COS 320. Compiling Techniques. Princeton University Spring Prof. David August. Adapted from slides by Aarne Ranta
Topic 6: Types COS 320 Compiling Techniques Princeton University Spring 2015 Prof. David August 1 Adapted from slides by Aarne Ranta Types What is a type? Type Checking: Helps find language-level errors:
More informationSemantic Analysis. Lecture 9. February 7, 2018
Semantic Analysis Lecture 9 February 7, 2018 Midterm 1 Compiler Stages 12 / 14 COOL Programming 10 / 12 Regular Languages 26 / 30 Context-free Languages 17 / 21 Parsing 20 / 23 Extra Credit 4 / 6 Average
More informationCS558 Programming Languages
CS558 Programming Languages Winter 2017 Lecture 4a Andrew Tolmach Portland State University 1994-2017 Semantics and Erroneous Programs Important part of language specification is distinguishing valid from
More informationG Programming Languages - Fall 2012
G22.2110-003 Programming Languages - Fall 2012 Lecture 3 Thomas Wies New York University Review Last week Names and Bindings Lifetimes and Allocation Garbage Collection Scope Outline Control Flow Sequencing
More informationProgrammiersprachen (Programming Languages)
2016-05-13 Preface Programmiersprachen (Programming Languages) coordinates: lecturer: web: usable for: requirements: No. 185.208, VU, 3 ECTS Franz Puntigam http://www.complang.tuwien.ac.at/franz/ps.html
More informationCS558 Programming Languages. Winter 2013 Lecture 3
CS558 Programming Languages Winter 2013 Lecture 3 1 NAMES AND BINDING One essential part of being a high-level language is having convenient names for things: variables constants types functions etc. classes
More informationInformatica 3 Syntax and Semantics
Informatica 3 Syntax and Semantics Marcello Restelli 9/15/07 Laurea in Ingegneria Informatica Politecnico di Milano Introduction Introduction to the concepts of syntax and semantics Binding Variables Routines
More informationProperties of an identifier (and the object it represents) may be set at
Properties of an identifier (and the object it represents) may be set at Compile-time These are static properties as they do not change during execution. Examples include the type of a variable, the value
More informationInterpreters. Prof. Clarkson Fall Today s music: Step by Step by New Kids on the Block
Interpreters Prof. Clarkson Fall 2017 Today s music: Step by Step by New Kids on the Block Review Previously in 3110: functional programming modular programming data structures Today: new unit of course:
More informationScope. Chapter Ten Modern Programming Languages 1
Scope Chapter Ten Modern Programming Languages 1 Reusing Names Scope is trivial if you have a unique name for everything: fun square a = a * a; fun double b = b + b; But in modern languages, we often use
More informationRun-time Environments - 2
Run-time Environments - 2 Y.N. Srikant Computer Science and Automation Indian Institute of Science Bangalore 560 012 NPTEL Course on Principles of Compiler Design Outline of the Lecture n What is run-time
More informationReading Assignment. Scanner. Read Chapter 3 of Crafting a Compiler.
Reading Assignment Source Program (Character Stream) Scanner Tokens Parser Abstract Syntax Tree (AST) Type Checker Decorated AST Read Chapter 3 of Crafting a Compiler. Translator Intermediate Representation
More informationCSE P 501 Compilers. Static Semantics Hal Perkins Winter /22/ Hal Perkins & UW CSE I-1
CSE P 501 Compilers Static Semantics Hal Perkins Winter 2008 1/22/2008 2002-08 Hal Perkins & UW CSE I-1 Agenda Static semantics Types Attribute grammars Representing types Symbol tables Note: this covers
More informationCS /534 Compiler Construction University of Massachusetts Lowell
CS 91.406/534 Compiler Construction University of Massachusetts Lowell Professor Li Xu Fall 2004 Lab Project 2: Parser and Type Checker for NOTHING Due: Sunday, November 14, 2004, 11:59 PM 1 Introduction
More informationProject Compiler. CS031 TA Help Session November 28, 2011
Project Compiler CS031 TA Help Session November 28, 2011 Motivation Generally, it s easier to program in higher-level languages than in assembly. Our goal is to automate the conversion from a higher-level
More informationOverview of Semantic Analysis. Lecture 9
Overview of Semantic Analysis Lecture 9 1 Midterm Thursday In class SCPD students come to campus for the exam Material through lecture 8 Open note Laptops OK, but no internet or computation 2 Outline The
More informationCS558 Programming Languages
CS558 Programming Languages Fall 2016 Lecture 3a Andrew Tolmach Portland State University 1994-2016 Formal Semantics Goal: rigorous and unambiguous definition in terms of a wellunderstood formalism (e.g.
More informationCS 314 Principles of Programming Languages
CS 314 Principles of Programming Languages Lecture 13: Names, Scopes and Bindings Zheng (Eddy) Zhang Rutgers University February 28, 2018 Review: Names, Scopes and Binding What s in a name? Each name means
More informationSpecial Topics: Programming Languages
Lecture #15 0 V22.0490.001 Special Topics: Programming Languages B. Mishra New York University. Lecture # 15 Lecture #15 1 Slide 1 Scope Issues Those features which describe and control the use of named
More informationCS152 Programming Language Paradigms Prof. Tom Austin, Fall Syntax & Semantics, and Language Design Criteria
CS152 Programming Language Paradigms Prof. Tom Austin, Fall 2014 Syntax & Semantics, and Language Design Criteria Lab 1 solution (in class) Formally defining a language When we define a language, we need
More informationAbout this exam review
Final Exam Review About this exam review I ve prepared an outline of the material covered in class May not be totally complete! Exam may ask about things that were covered in class but not in this review
More informationRun-time Environments. Lecture 13. Prof. Alex Aiken Original Slides (Modified by Prof. Vijay Ganesh) Lecture 13
Run-time Environments Lecture 13 by Prof. Vijay Ganesh) Lecture 13 1 What have we covered so far? We have covered the front-end phases Lexical analysis (Lexer, regular expressions,...) Parsing (CFG, Top-down,
More informationCS558 Programming Languages
CS558 Programming Languages Fall 2016 Lecture 7a Andrew Tolmach Portland State University 1994-2016 Values and Types We divide the universe of values according to types A type is a set of values and a
More informationCSE450. Translation of Programming Languages. Lecture 11: Semantic Analysis: Types & Type Checking
CSE450 Translation of Programming Languages Lecture 11: Semantic Analysis: Types & Type Checking Structure Project 1 - of a Project 2 - Compiler Today! Project 3 - Source Language Lexical Analyzer Syntax
More informationCA Compiler Construction
CA4003 - Compiler Construction Semantic Analysis David Sinclair Semantic Actions A compiler has to do more than just recognise if a sequence of characters forms a valid sentence in the language. It must
More informationArray. Prepared By - Rifat Shahriyar
Java More Details Array 2 Arrays A group of variables containing values that all have the same type Arrays are fixed length entities In Java, arrays are objects, so they are considered reference types
More information