[SOLVED] COMP 302: Programming Languages and Paradigms

COMP 302: Programming Languages and Paradigms
Week 1: Basic Intro to OCaml Prof. Xujie Si

A brief history of OCaml

Copyright By Assignmentchef assignmentchef

A brief history of OCaml
Meta-language (ML), 1970s
Designed for developing theorem provers
Logic for Computable Functions (LCF) theorem-proving project
Standard ML, 1980s Caml, 1980s
Categorical Abstract Machine Language (CAML)
Caml Light, 1990s
New implementation of Caml (based on bytecode interpreter) Highly portable
Caml Special Light, 1990s
Improvement of Caml Light, with a native-code compiler
Objective Caml, 1990s OCaml, 2011

A brief history of OCaml
Meta-language (ML), 1970s
Designed for developing theorem provers
Logic for Computable Functions (LCF) theorem-proving project
Standard ML, 1980s Caml, 1980s
Categorical Abstract Machine Language (CAML)
Caml Light, 1990s
New implementation of Caml (based on bytecode interpreter) Highly portable
Caml Special Light, 1990s
Improvement of Caml Light, with a native-code compiler
Objective Caml, 1990s OCaml, 2011

A brief history of OCaml
Meta-language (ML), 1970s
Designed for developing theorem provers
Logic for Computable Functions (LCF) theorem-proving project
Standard ML, 1980s Caml, 1980s
Categorical Abstract Machine Language (CAML)
Caml Light, 1990s
New implementation of Caml (based on bytecode interpreter) Highly portable
Caml Special Light, 1990s
Improvement of Caml Light, with a native-code compiler
Objective Caml, 1990s OCaml, 2011

A brief history of OCaml
Meta-language (ML), 1970s
Designed for developing theorem provers
Logic for Computable Functions (LCF) theorem-proving project
Standard ML, 1980s Caml, 1980s
Categorical Abstract Machine Language (CAML)
Caml Light, 1990s
New implementation of Caml (based on bytecode interpreter) Highly portable
Caml Special Light, 1990s
Improvement of Caml Light, with a native-code compiler
Objective Caml, 1990s OCaml, 2011

A brief history of OCaml
Meta-language (ML), 1970s
Designed for developing theorem provers
Logic for Computable Functions (LCF) theorem-proving project
Standard ML, 1980s Caml, 1980s
Categorical Abstract Machine Language (CAML)
Caml Light, 1990s
New implementation of Caml (based on bytecode interpreter) Highly portable
Caml Special Light, 1990s
Improvement of Caml Light, with a native-code compiler
Objective Caml, 1990s OCaml, 2011

A brief history of OCaml
Meta-language (ML), 1970s
Designed for developing theorem provers
Logic for Computable Functions (LCF) theorem-proving project
Standard ML, 1980s Caml, 1980s
Categorical Abstract Machine Language (CAML)
Caml Light, 1990s
New implementation of Caml (based on bytecode interpreter) Highly portable
Caml Special Light, 1990s
Improvement of Caml Light, with a native-code compiler
Objective Caml, 1990s OCaml, 2011

A brief history of OCaml
Meta-language (ML), 1970s
Designed for developing theorem provers
Logic for Computable Functions (LCF) theorem-proving project
Standard ML, 1980s Caml, 1980s
Categorical Abstract Machine Language (CAML)
Caml Light, 1990s
New implementation of Caml (based on bytecode interpreter) Highly portable
Caml Special Light, 1990s
Improvement of Caml Light, with a native-code compiler
Objective Caml, 1990s OCaml, 2011

Web-based Programming Platform for OCaml

Web-based Programming Platform for OCaml
Any browser can be your IDE (Yes, offline is completely fine!)
Immediate Feedback on assignments via autograder
Playground provides direct access to all the code discussed in class and you can directly interact with it
Toplevel allows you to execute and test your program via the Read- Eval-Print Loop (REPL)

Web-based Programming Platform for OCaml
Any browser can be your IDE (Yes, offline is completely fine!)
Immediate Feedback on assignments via autograder
Playground provides direct access to all the code discussed in class and you can directly interact with it
Toplevel allows you to execute and test your program via the Read- Eval-Print Loop (REPL)

Web-based Programming Platform for OCaml
Any browser can be your IDE (Yes, offline is completely fine!)
Immediate Feedback on assignments via autograder
Playground provides direct access to all the code discussed in class and you can directly interact with it
Toplevel allows you to execute and test your program via the Read- Eval-Print Loop (REPL)

Web-based Programming Platform for OCaml
Any browser can be your IDE (Yes, offline is completely fine!)
Immediate Feedback on assignments via autograder
Playground provides direct access to all the code discussed in class and you can directly interact with it
Toplevel allows you to execute and test your program via the Read- Eval-Print Loop (REPL)

Web-based Programming Platform for OCaml
Any browser can be your IDE (Yes, offline is completely fine!)
Immediate Feedback on assignments via autograder
Playground provides direct access to all the code discussed in class and you can directly interact with it
Toplevel allows you to execute and test your program via the Read- Eval-Print Loop (REPL)
a compiler from OCaml bytecode programs to JavaScript.

Create a LearnOCaml Account
https://winter2022-comp302.cs.mcgill.ca/
Your 9-digit student ID
You have to remember this new token!!
You will only need this (secret) token later on

What is a variable in functional programming?
Just a name for a value & cannot vary
Imagine they were variables in math equations
Conceptually, there is no memory (thus no mutation)

What is a variable in functional programming?
Just a name for a value & cannot vary
Imagine they were variables in math equations
Conceptually, there is no memory (thus no mutation)

What is a variable in functional programming?
Just a name for a value & cannot vary
Imagine they were variables in math equations
Conceptually, there is no memory (thus no mutation)
Do x and y vary here?

What is a variable in functional programming?
Just a name for a value & cannot vary
Imagine they were variables in math equations
Conceptually, there is no memory (thus no mutation)
y=4-x x=4-y
Do x and y vary here?

What is a variable in functional programming?
Just a name for a value & cannot vary
Imagine they were variables in math equations
Conceptually, there is no memory (thus no mutation)
y=4-x x=4-y
Do x and y vary here?
Are these two equations equivalent? Should they?

What is a variable in functional programming?
Just a name for a value & cannot vary
Imagine they were variables in math equations
Conceptually, there is no memory (thus no mutation)
y=4-x x=4-y
Do x and y vary here?
Are these two equations equivalent? Should they?
However, in imperative programming languages (e.g., C, C++, Java, Python, etc.), the meaning of these two equations are quite different

What is a variable in functional programming?
Just a name for a value & cannot vary
Imagine they were variables in math equations
Conceptually, there is no memory (thus no mutation)
y=4-x x=4-y
Do x and y vary here?
Are these two equations equivalent? Should they?
However, in imperative programming languages (e.g., C, C++, Java, Python, etc.), the meaning of these two equations are quite different
(Informal) quiz: What is Lvalue (Rvalue)? Share your answers on Ed!!

What is a value?

What is a value?
Can you give some examples of values? 1, 2, 3
true, false
Or even simpler: ()
How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)What is a value? Can you give some examples of values? 1, 2, 3 true, false Or even simpler: () How about 1 + 2 or 1 < 2? They are expressions (NOT values), which can be evaluated into values. Are values expressions? How about a function? Is it a value or an expression or something else? Function is also a value! (aka. functions are first-class citizen!)(informal) Quiz: What is the difference between a statement and an expression? Please share your answer on Ed!!Variable binding / Naming valuesVariable binding / Naming values Let-expression let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
DoesXbind to3+3or6?

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
DoesXbind to3+3or6?

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Out of scope
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Out of scope
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10 x =10

Variable binding / Naming values
Let-expression
let = in
let x = 3 + 3 ;;
let y = x + x + x ;;
let x = 10 in x + y (Note: no double semicolon here)
Nested let-expressions
let x = 3 in (let y = x + x + x in x + y)
Out of scope
Overshadowing (binding stack)
let x = 10 in (let x = x + x in x + x + x) + x
Empty x =10 x =10

What is a type?

What is a type?
Examples:
int, float, bool, char, string
int -> int, string -> int
OCaml convention: type names are all in lower case
Types classify expressions (by their values)
An expression can only have one type, correct or wrong?
Statically typed vs dynamically typed
Types can be inferred before executions
Types are determined at the moment of being executed

What is a type?
Examples:
int, float, bool, char, string
int -> int, string -> int
OCaml convention: type names are all in lower case
Types classify expressions (by their values)
An expression can only have one type, correct or wrong?
Statically typed vs dynamically typed
Types can be inferred before executions
Types are determined at the moment of being executed

What is a type?
Examples:
int, float, bool, char, string
int -> i

CS: assignmentchef QQ: 1823890830 Email: [email protected]