From c29305e60c5f83f5803f7d7f408cf6a98ba155c9 Mon Sep 17 00:00:00 2001 From: Greg Hendershott Date: Sat, 28 Sep 2013 14:00:34 -0400 Subject: [PATCH] Regen HTML for gh-pages --- Transform_.html | 4 +++- all.html | 8 ++++---- index.html | 2 +- 3 files changed, 8 insertions(+), 6 deletions(-) diff --git a/Transform_.html b/Transform_.html index 77f0627..ae58e5d 100644 --- a/Transform_.html +++ b/Transform_.html @@ -36,7 +36,9 @@ and so on recursively—which is what

When we want to transform syntax, we’ll generally take the pieces we were given, maybe rearrange their order, perhaps change some of the pieces, and often introduce brand-new pieces.

3.3 Actually transforming the input

Let’s write a transformer function that reverses the syntax it was -given:

the values at the end allows the result to evaluate nicely. Try (reverse-me "backwards" "am" "i") to see why it’s handy.

> (define-syntax (reverse-me stx)
    (datum->syntax stx (reverse (cdr (syntax->datum stx)))))
> (reverse-me "backwards" "am" "i" values)

"i"

"am"

"backwards"

Understand Yoda, can we. Great, but how does this work?

First we take the input syntax, and give it to +given:

The values at the end of the example allows the +result to evaluate nicely. Try +(reverse-me "backwards" "am" "i") to see why it’s handy.

> (define-syntax (reverse-me stx)
    (datum->syntax stx (reverse (cdr (syntax->datum stx)))))
> (reverse-me "backwards" "am" "i" values)

"i"

"am"

"backwards"

Understand Yoda, can we. Great, but how does this work?

First we take the input syntax, and give it to syntax->datum. This converts the syntax into a plain old list:

> (syntax->datum #'(reverse-me "backwards" "am" "i" values))

'(reverse-me "backwards" "am" "i" values)

Using cdr slices off the first item of the list, reverse-me, leaving the remainder: diff --git a/all.html b/all.html index 2477d86..1996fc8 100644 --- a/all.html +++ b/all.html @@ -1,6 +1,6 @@ Fear of Macros

►Fear of Macros
1 Preface
2 Our plan of attack
3 Transform!
3.1 What is a syntax transformer?
3.2 What’s the input?
3.3 Actually transforming the input
3.4 Compile time vs. run time
3.5 begin-for-syntax
4 Pattern matching:   syntax-case and syntax-rules
4.1 Pattern variable vs. template—fight!
4.1.1 with-syntax
4.1.2 with-syntax*
4.1.3 format-id
4.1.4 Another example
4.2 Making our own struct
4.3 Using dot notation for nested hash lookups
5 Syntax parameters
6 What’s the point of splicing-let?
7 Robust macros:   syntax-parse
7.1 Error-handling strategies for functions
7.2 Error-handling strategies for macros
7.3 Using syntax/  parse
8 References and Acknowledgments
9 Epilogue

Fear of Macros

Greg Hendershott

-
Copyright (c) 2012-2013 by Greg Hendershott. All rights reserved.
Last updated 2013-09-28T11:41:22
Feedback and corrections are welcome here.

Contents:

    1 Preface

    2 Our plan of attack

    3 Transform!

      3.1 What is a syntax transformer?

      3.2 What’s the input?

      3.3 Actually transforming the input

      3.4 Compile time vs. run time

      3.5 begin-for-syntax

    4 Pattern matching: syntax-case and syntax-rules

      4.1 Pattern variable vs. template—fight!

        4.1.1 with-syntax

        4.1.2 with-syntax*

        4.1.3 format-id

        4.1.4 Another example

      4.2 Making our own struct

      4.3 Using dot notation for nested hash lookups

    5 Syntax parameters

    6 What’s the point of splicing-let?

    7 Robust macros: syntax-parse

      7.1 Error-handling strategies for functions

      7.2 Error-handling strategies for macros

      7.3 Using syntax/parse

    8 References and Acknowledgments

    9 Epilogue

1 Preface

I learned Racket after 25 years of mostly using C and C++.

Some psychic whiplash resulted.

"All the parentheses" was actually not a big deal. Instead, the first +

Copyright (c) 2012-2013 by Greg Hendershott. All rights reserved.
Last updated 2013-09-28T13:57:58
Feedback and corrections are welcome here.

Contents:

    1 Preface

    2 Our plan of attack

    3 Transform!

      3.1 What is a syntax transformer?

      3.2 What’s the input?

      3.3 Actually transforming the input

      3.4 Compile time vs. run time

      3.5 begin-for-syntax

    4 Pattern matching: syntax-case and syntax-rules

      4.1 Pattern variable vs. template—fight!

        4.1.1 with-syntax

        4.1.2 with-syntax*

        4.1.3 format-id

        4.1.4 Another example

      4.2 Making our own struct

      4.3 Using dot notation for nested hash lookups

    5 Syntax parameters

    6 What’s the point of splicing-let?

    7 Robust macros: syntax-parse

      7.1 Error-handling strategies for functions

      7.2 Error-handling strategies for macros

      7.3 Using syntax/parse

    8 References and Acknowledgments

    9 Epilogue

1 Preface

I learned Racket after 25 years of mostly using C and C++.

Some psychic whiplash resulted.

"All the parentheses" was actually not a big deal. Instead, the first mind warp was functional programming. Before long I wrapped my brain around it, and went on to become comfortable and effective with many other aspects and features of Racket.

But two final frontiers remained: Macros and continuations.

I found that simple macros were easy and understandable, plus there @@ -79,9 +79,9 @@ and so on recursively—which is what

When we want to transform syntax, we’ll generally take the pieces we were given, maybe rearrange their order, perhaps change some of the pieces, and often introduce brand-new pieces.

3.3 Actually transforming the input

Let’s write a transformer function that reverses the syntax it was -given:

the values at the end allows the result to -evaluate nicely. Try (reverse-me "backwards" "am" "i") to -see why it’s handy.

> (define-syntax (reverse-me stx)
    (datum->syntax stx (reverse (cdr (syntax->datum stx)))))
> (reverse-me "backwards" "am" "i" values)

"i"

"am"

"backwards"

Understand Yoda, can we. Great, but how does this work?

First we take the input syntax, and give it to +given:

The values at the end of the example allows the +result to evaluate nicely. Try +(reverse-me "backwards" "am" "i") to see why it’s handy.

> (define-syntax (reverse-me stx)
    (datum->syntax stx (reverse (cdr (syntax->datum stx)))))
> (reverse-me "backwards" "am" "i" values)

"i"

"am"

"backwards"

Understand Yoda, can we. Great, but how does this work?

First we take the input syntax, and give it to syntax->datum. This converts the syntax into a plain old list:

> (syntax->datum #'(reverse-me "backwards" "am" "i" values))

'(reverse-me "backwards" "am" "i" values)

Using cdr slices off the first item of the list, reverse-me, leaving the remainder: diff --git a/index.html b/index.html index aebe792..3fb1220 100644 --- a/index.html +++ b/index.html @@ -1,3 +1,3 @@ Fear of Macros

▼Fear of Macros
    ← prev  up  next → 

Fear of Macros

Greg Hendershott

-
Copyright (c) 2012-2013 by Greg Hendershott. All rights reserved.
Last updated 2013-09-28T11:41:16
Feedback and corrections are welcome here.

Contents:

    1 Preface

    2 Our plan of attack

    3 Transform!

      3.1 What is a syntax transformer?

      3.2 What’s the input?

      3.3 Actually transforming the input

      3.4 Compile time vs. run time

      3.5 begin-for-syntax

    4 Pattern matching: syntax-case and syntax-rules

      4.1 Pattern variable vs. template—fight!

        4.1.1 with-syntax

        4.1.2 with-syntax*

        4.1.3 format-id

        4.1.4 Another example

      4.2 Making our own struct

      4.3 Using dot notation for nested hash lookups

    5 Syntax parameters

    6 What’s the point of splicing-let?

    7 Robust macros: syntax-parse

      7.1 Error-handling strategies for functions

      7.2 Error-handling strategies for macros

      7.3 Using syntax/parse

    8 References and Acknowledgments

    9 Epilogue

    ← prev  up  next → 
 
\ No newline at end of file +
Copyright (c) 2012-2013 by Greg Hendershott. All rights reserved.
Last updated 2013-09-28T13:57:52
Feedback and corrections are welcome here.

Contents:

    1 Preface

    2 Our plan of attack

    3 Transform!

      3.1 What is a syntax transformer?

      3.2 What’s the input?

      3.3 Actually transforming the input

      3.4 Compile time vs. run time

      3.5 begin-for-syntax

    4 Pattern matching: syntax-case and syntax-rules

      4.1 Pattern variable vs. template—fight!

        4.1.1 with-syntax

        4.1.2 with-syntax*

        4.1.3 format-id

        4.1.4 Another example

      4.2 Making our own struct

      4.3 Using dot notation for nested hash lookups

    5 Syntax parameters

    6 What’s the point of splicing-let?

    7 Robust macros: syntax-parse

      7.1 Error-handling strategies for functions

      7.2 Error-handling strategies for macros

      7.3 Using syntax/parse

    8 References and Acknowledgments

    9 Epilogue

    ← prev  up  next → 
 
\ No newline at end of file