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|
@require: class-slydifi/theme/akasaka
@require: code-printer/code-design
@require: code-printer/code-printer
@require: code-printer/code-syntax
@require: code-printer/code-theme
@require: figbox/figbox
let-block +code-block source keywords =
let syntax =
let void-syntax-rule = CodePrinter.syntax-rule-fun (fun _ -> None) in
CodePrinter.make-syntax (|
line-comment = void-syntax-rule;
block-comment = void-syntax-rule;
string = void-syntax-rule;
keywords = keywords;
identifier = void-syntax-rule;
others = [];
|)
in
'<
+code-printer?:(
CodePrinter.make-config syntax CodeTheme.iceberg-light
|> CodePrinter.set-number-fun CodeDesign.number-fun-null
)(source);
>
let-block +code-block-php source =
'<
+code-printer?:(
CodePrinter.make-config CodeSyntax.php CodeTheme.iceberg-light
|> CodePrinter.set-number-fun CodeDesign.number-fun-null
)(source);
>
let catchline-try = `<?php
try {
f(3);
} catch (Throwable $e) {
do {
printf('%c', $e->getLine() + 21);
} while ($e = $e->getPrevious());
echo "\n";
}`
let catchline-fn-f = `function f(int $i) {
if ($i < 0) return;
try {
match ($i) {
0 => X, // 14行目
// (間の空行は省略)
2 => X, // 51行目
// (間の空行は省略)
1, 3 => X, // 59行目
};
} finally {
f($i - 1);
}
}`
let catchline-fn-f-with-comments = `function f(int $i) {
if ($i < 0) return;
try {
match ($i) {
0 => X, // 14行目: エラー！未定義の定数！
// (間の空行は省略)
2 => X, // 51行目: エラー！未定義の定数！
// (間の空行は省略)
1, 3 => X, // 59行目: エラー！未定義の定数！
};
} finally {
f($i - 1);
}
}`
let error-chain = `<?php
try {
throw new \Exception("a");
} finally {
throw new \Exception("b");
}
`
open FigBox
in
document '<
+make-title(|
title = {
|PHPerKaigi 2023 のトークン問題で
|ボツにした問題を供養する
|};
author = {|nsfisis (いまむら)|};
date = {|第149回PHP勉強会＠東京|};
|);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+frame{自己紹介}<
+fig-center(vconcat [
hconcat [
gap 20pt;
textbox{nsfisis (いまむら)};
gap 20pt;
include-image 50pt `assets/me.jpeg`;
];
gap 20pt;
textbox{\@ デジタルサーカス株式会社};
]);
>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+frame{PHPerKaigiとは、トークン問題とは}<
+fig-center(vconcat [
gap 20pt;
textbox{時間がないので省略。長谷川さんに聞いてください};
gap 20pt;
textbox{変わったPHPプログラムを持ってきたので解説します};
]);
>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+frame{Catchline}<
+code-block-php(catchline-try);
>
+frame{Catchline}<
+code-block-php(catchline-fn-f);
>
+frame{Catchline}<
+code-block-php(catchline-try);
+p{
\inline-code(`f()`);を呼び出して\inline-code(`Throwable`);を捕まえ、何かする
}
>
+frame{Catchline}<
+code-block-php(catchline-fn-f-with-comments);
>
+frame{Catchline}<
+code-block-php(catchline-try);
+p{
\inline-code(`\Throwable::getPrevious()`);を順に辿り、(エラーの発生した行数+21)を
}
+p{
ASCIIコード\text-color(Color.gray(0.75)){[1]}と見做して出力
}
+p{
\text-color(Color.gray(0.75)){[1]: VAS Syndrome}
}
>
+frame{Catchline}<
+p{
\inline-code(`\Throwable::getPrevious()`);
}
+p{
発生したエラーの1つ前のエラー(=大本の原因)
}
+p{
通常は例外クラスのコンストラクタに渡して設定する
}
>
+frame{Catchline}<
+code-block-php(error-chain);
+p{
\inline-code(`finally`);節の中で例外を発生させると、PHPの処理系が勝手に`$previous`を設定する
}
>
+frame{Catchline}<
+code-block-php(catchline-fn-f-with-comments);
>
+frame{Catchline}<
+code-block-php(catchline-try);
+p{
(エラーの発生した行数+21)をASCIIコードと見做して出力
}
>
+frame{Catchline}<
+code-block-php(catchline-fn-f-with-comments);
>
+frame{Catchline}<
+p{
\listing{
* 14 + 21 = 35 (\inline-code(`#`);)
* 51 + 21 = 72 (\inline-code(`H`);)
* 59 + 21 = 80 (\inline-code(`P`);)
}
}
+p{
組み合わせて\inline-code(`#PHP`);に
}
>
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+frame{おわりに}<
+fig-center(vconcat ?:(align-center) [
gap 20pt;
textbox{来たる3月のPHPerKaigi 2023で};
gap 20pt;
textbox{これより数段凝った問題を5つ出題します！};
gap 20pt;
textbox{みなさまの挑戦をお待ちしております！};
]);
>
>
|
