Fixed syntax for assigning anchors.
This commit is contained in:
Wen Kokke
parent
4b5d775ba1
commit
07d082c9db
17 changed files with 54 additions and 53 deletions
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@ -23,7 +23,7 @@ $(SITE_DIR)/plfa.epub: \
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$(RAW_DIR)/epub.md $(EPUB_DIR)/epub.css $(RAW_DIR)/epub.xml $(FRANKENFONT) \
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$(MD_FILES) $(EPUB_LUA_SCRIPTS) | setup-install-pandoc
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@echo "Building EPUB"
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$(PANDOC) \
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@$(PANDOC) \
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--strip-comments \
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--css=$(EPUB_DIR)/epub.css \
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--epub-embed-font=$(FRANKENFONT) \
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@ -33,6 +33,7 @@ $(SITE_DIR)/plfa.epub: \
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--lua-filter=$(EPUB_LUA_DIR)/remove-badges.lua -M badge-url=https://img.shields.io/badge/ \
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--lua-filter=$(EPUB_LUA_DIR)/epub-clean-html.lua \
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--lua-filter=$(EPUB_LUA_DIR)/single-file-links.lua \
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--lua-filter=$(EPUB_LUA_DIR)/single-file-identifiers.lua \
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--standalone \
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--toc --toc-depth=2 \
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--epub-chapter-level=2 \
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@ -8,7 +8,7 @@
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-- [text](/chapter/) -> [text](#chapter)
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--
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-- All other Links are ignored.
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function Link (el)
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function Link(el)
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local n
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-- Case 1:
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el.target, n = el.target:gsub("^/(%w+)/#([%w-]+)$", "#%1-%2")
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@ -4,6 +4,6 @@ title: "PLFA as EPUB"
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It has been just over a year and a half since this feature was first requested in [#112][issue112]… Thanks to hard work by [Michael Reed][mreed20], and a little elbow grease on our part, it is finally here! [An EPUB version of PLFA!][EPUB]
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[EPUB]: https://plfa.github.io/out/epub/plfa.epub
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[EPUB]: https://plfa.github.io/epub/plfa.epub
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[issue112]: https://github.com/plfa/plfa.github.io/issues/112
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[mreed20]: https://github.com/mreed20
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@ -21,8 +21,8 @@ As always, bug reports and pull requests are very, very welcome!
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[Altariarite]: https://github.com/Altariarite
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[mreed20]: https://github.com/mreed20
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[PDF]: https://plfa.github.io/out/epub/plfa.pdf
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[EPUB]: https://plfa.github.io/out/epub/plfa.epub
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[PDF]: https://plfa.github.io/epub/plfa.pdf
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[EPUB]: https://plfa.github.io/epub/plfa.epub
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[issue577]: https://github.com/plfa/plfa.github.io/issues/577
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[issue578]: https://github.com/plfa/plfa.github.io/issues/578
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@ -536,7 +536,7 @@ Show empty is the right identity of sums up to isomorphism.
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-- Your code goes here
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```
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## Implication is function {name=implication}
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## Implication is function {#implication}
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Given two propositions `A` and `B`, the implication `A → B` holds if
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whenever `A` holds then `B` must also hold. We formalise implication using
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@ -561,7 +561,7 @@ postulate
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-- Your code goes here
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```
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## Proof by reflection {name=proof-by-reflection}
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## Proof by reflection {#proof-by-reflection}
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Let's revisit our definition of monus from
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Chapter [Naturals](/Naturals/).
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@ -132,7 +132,7 @@ Again, a useful exercise is to carry out an interactive development,
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checking how Agda's knowledge changes as each of the two arguments is
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instantiated.
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## Congruence and substitution {name=cong}
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## Congruence and substitution {#cong}
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Equality satisfies _congruence_. If two terms are equal,
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they remain so after the same function is applied to both:
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@ -635,7 +635,7 @@ Jesper Cockx, Dominique Devries, Andreas Nuyts, and Philip Wadler,
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draft, 2017.)
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## Universe polymorphism {name=unipoly}
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## Universe polymorphism {#unipoly}
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As we have seen, not every type belongs to `Set`, but instead every
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type belongs somewhere in the hierarchy `Set₀`, `Set₁`, `Set₂`, and so on,
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@ -71,7 +71,7 @@ distributes over another operator. A careful author will often call
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out these properties---or their lack---for instance by pointing out
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that a newly introduced operator is associative but not commutative.
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#### Exercise `operators` (practice) {name=operators}
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#### Exercise `operators` (practice) {#operators}
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Give another example of a pair of operators that have an identity
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and are associative, commutative, and distribute over one another.
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@ -599,7 +599,7 @@ the main proposition first, and the equations required to do so
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will suggest what lemmas to prove.
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## Our first corollary: rearranging {name=sections}
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## Our first corollary: rearranging {#sections}
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We can apply associativity to rearrange parentheses however we like.
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Here is an example:
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@ -695,7 +695,7 @@ judgments where the first number is less than _m_.
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There is also a completely finite approach to generating the same equations,
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which is left as an exercise for the reader.
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#### Exercise `finite-|-assoc` (stretch) {name=finite-plus-assoc}
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#### Exercise `finite-|-assoc` (stretch) {#finite-plus-assoc}
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Write out what is known about associativity of addition on each of the
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first four days using a finite story of creation, as
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@ -857,7 +857,7 @@ typing `C-c C-r` will fill it in, completing the proof:
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+-assoc′ (suc m) n p rewrite +-assoc′ m n p = refl
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#### Exercise `+-swap` (recommended) {name=plus-swap}
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#### Exercise `+-swap` (recommended) {#plus-swap}
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Show
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@ -872,7 +872,7 @@ is associative and commutative.
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```
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#### Exercise `*-distrib-+` (recommended) {name=times-distrib-plus}
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#### Exercise `*-distrib-+` (recommended) {#times-distrib-plus}
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Show multiplication distributes over addition, that is,
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@ -885,7 +885,7 @@ for all naturals `m`, `n`, and `p`.
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```
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#### Exercise `*-assoc` (recommended) {name=times-assoc}
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#### Exercise `*-assoc` (recommended) {#times-assoc}
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Show multiplication is associative, that is,
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@ -898,7 +898,7 @@ for all naturals `m`, `n`, and `p`.
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```
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#### Exercise `*-comm` (practice) {name=times-comm}
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#### Exercise `*-comm` (practice) {#times-comm}
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Show multiplication is commutative, that is,
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@ -912,7 +912,7 @@ you will need to formulate and prove suitable lemmas.
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```
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#### Exercise `0∸n≡0` (practice) {name=zero-monus}
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#### Exercise `0∸n≡0` (practice) {#zero-monus}
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Show
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@ -925,7 +925,7 @@ for all naturals `n`. Did your proof require induction?
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```
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#### Exercise `∸-|-assoc` (practice) {name=monus-plus-assoc}
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#### Exercise `∸-|-assoc` (practice) {#monus-plus-assoc}
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Show that monus associates with addition, that is,
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@ -949,7 +949,7 @@ Show the following three laws
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for all `m`, `n`, and `p`.
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#### Exercise `Bin-laws` (stretch) {name=Bin-laws}
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#### Exercise `Bin-laws` (stretch) {#Bin-laws}
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Recall that
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Exercise [Bin](/Naturals/#Bin)
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@ -83,7 +83,7 @@ g ∘′ f = λ x → g (f x)
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```
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## Extensionality {name=extensionality}
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## Extensionality {#extensionality}
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Extensionality asserts that the only way to distinguish functions is
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by applying them; if two functions applied to the same argument always
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@ -450,7 +450,7 @@ postulate
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-- Your code goes here
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```
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#### Exercise `_⇔_` (practice) {name=iff}
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#### Exercise `_⇔_` (practice) {#iff}
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Define equivalence of propositions (also known as "if and only if") as follows:
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```
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@ -465,7 +465,7 @@ Show that equivalence is reflexive, symmetric, and transitive.
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-- Your code goes here
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```
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#### Exercise `Bin-embedding` (stretch) {name=Bin-embedding}
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#### Exercise `Bin-embedding` (stretch) {#Bin-embedding}
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Recall that Exercises
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[Bin](/Naturals/#Bin) and
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@ -458,7 +458,7 @@ _ =
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```
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Now the time to reverse a list is linear in the length of the list.
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## Map {name=Map}
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## Map {#Map}
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Map applies a function to every element of a list to generate a corresponding list.
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Map is an example of a _higher-order function_, one which takes a function as an
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@ -558,7 +558,7 @@ Define a suitable map operator over trees:
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-- Your code goes here
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```
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## Fold {name=Fold}
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## Fold {#Fold}
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Fold takes an operator and a value, and uses the operator to combine
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each of the elements of the list, taking the given value as the result
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@ -833,7 +833,7 @@ Show that if `_⊗_` and `e` form a monoid, then `foldr _⊗_ e` and
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```
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## All {name=All}
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## All {#All}
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We can also define predicates over lists. Two of the most important
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are `All` and `Any`.
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@ -76,7 +76,7 @@ after zero; and `2` is shorthand for `suc (suc zero)`, which is the
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same as `suc 1`, the successor of one; and `3` is shorthand for the
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successor of two; and so on.
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#### Exercise `seven` (practice) {name=seven}
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#### Exercise `seven` (practice) {#seven}
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Write out `7` in longhand.
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@ -287,7 +287,7 @@ Parentheses and semicolons are among the few characters that cannot
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appear in names, so we do not need extra spaces in the `using` list.
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## Operations on naturals are recursive functions {name=plus}
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## Operations on naturals are recursive functions {#plus}
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Now that we have the natural numbers, what can we do with them?
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For instance, can we define arithmetic operations such as
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@ -425,7 +425,7 @@ is not like testimony in a court which must be weighed to determine
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whether the witness is trustworthy. Rather, it is ironclad. The
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other word for evidence, which we will use interchangeably, is _proof_.
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#### Exercise `+-example` (practice) {name=plus-example}
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#### Exercise `+-example` (practice) {#plus-example}
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Compute `3 + 4`, writing out your reasoning as a chain of equations, using the equations for `+`.
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@ -486,7 +486,7 @@ Here we have omitted the signature declaring `_ : 2 * 3 ≡ 6`, since
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it can easily be inferred from the corresponding term.
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#### Exercise `*-example` (practice) {name=times-example}
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#### Exercise `*-example` (practice) {#times-example}
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Compute `3 * 4`, writing out your reasoning as a chain of equations, using the equations for `*`.
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(You do not need to step through the evaluation of `+`.)
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@ -496,7 +496,7 @@ Compute `3 * 4`, writing out your reasoning as a chain of equations, using the e
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```
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#### Exercise `_^_` (recommended) {name=power}
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#### Exercise `_^_` (recommended) {#power}
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Define exponentiation, which is given by the following equations:
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@ -566,7 +566,7 @@ _ =
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∎
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```
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#### Exercise `∸-example₁` and `∸-example₂` (recommended) {name=monus-examples}
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#### Exercise `∸-example₁` and `∸-example₂` (recommended) {#monus-examples}
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Compute `5 ∸ 3` and `3 ∸ 5`, writing out your reasoning as a chain of equations.
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@ -701,7 +701,7 @@ definitions is quite similar. They might be considered two sides of
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the same coin.
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## The story of creation, finitely {name=finite-creation}
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## The story of creation, finitely {#finite-creation}
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The above story was told in a stratified way. First, we create
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the infinite set of naturals. We take that set as given when
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@ -872,7 +872,7 @@ Haskell requires time proportional to the sum of the logarithms of
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_m_ and _n_.
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#### Exercise `Bin` (stretch) {name=Bin}
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#### Exercise `Bin` (stretch) {#Bin}
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A more efficient representation of natural numbers uses a binary
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rather than a unary system. We represent a number as a bitstring:
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@ -438,7 +438,7 @@ postulate
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Does the converse hold? If so, prove; if not, explain why.
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#### Exercise `Bin-isomorphism` (stretch) {name=Bin-isomorphism}
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#### Exercise `Bin-isomorphism` (stretch) {#Bin-isomorphism}
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Recall that Exercises
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[Bin](/Naturals/#Bin),
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@ -241,7 +241,7 @@ lack---for instance by saying that a newly introduced relation is a
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partial order but not a total order.
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#### Exercise `orderings` (practice) {name=orderings}
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#### Exercise `orderings` (practice) {#orderings}
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Give an example of a preorder that is not a partial order.
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@ -359,7 +359,7 @@ and `suc n ≤ suc m` and must show `suc m ≡ suc n`. The inductive
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hypothesis `≤-antisym m≤n n≤m` establishes that `m ≡ n`, and our goal
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follows by congruence.
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#### Exercise `≤-antisym-cases` (practice) {name=leq-antisym-cases}
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#### Exercise `≤-antisym-cases` (practice) {#leq-antisym-cases}
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The above proof omits cases where one argument is `z≤n` and one
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argument is `s≤s`. Why is it ok to omit them?
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@ -559,7 +559,7 @@ Show that multiplication is monotonic with regard to inequality.
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```
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## Strict inequality {name=strict-inequality}
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## Strict inequality {#strict-inequality}
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We can define strict inequality similarly to inequality:
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```
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@ -597,7 +597,7 @@ and conversely. One can then give an alternative derivation of the
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properties of strict inequality, such as transitivity, by
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exploiting the corresponding properties of inequality.
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#### Exercise `<-trans` (recommended) {name=less-trans}
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#### Exercise `<-trans` (recommended) {#less-trans}
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Show that strict inequality is transitive.
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@ -605,7 +605,7 @@ Show that strict inequality is transitive.
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-- Your code goes here
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```
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#### Exercise `trichotomy` (practice) {name=trichotomy}
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#### Exercise `trichotomy` (practice) {#trichotomy}
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Show that strict inequality satisfies a weak version of trichotomy, in
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the sense that for any `m` and `n` that one of the following holds:
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@ -623,7 +623,7 @@ similar to that used for totality.
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-- Your code goes here
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```
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#### Exercise `+-mono-<` (practice) {name=plus-mono-less}
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#### Exercise `+-mono-<` (practice) {#plus-mono-less}
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Show that addition is monotonic with respect to strict inequality.
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As with inequality, some additional definitions may be required.
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@ -632,7 +632,7 @@ As with inequality, some additional definitions may be required.
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-- Your code goes here
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```
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#### Exercise `≤-iff-<` (recommended) {name=leq-iff-less}
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#### Exercise `≤-iff-<` (recommended) {#leq-iff-less}
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Show that `suc m ≤ n` implies `m < n`, and conversely.
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@ -640,7 +640,7 @@ Show that `suc m ≤ n` implies `m < n`, and conversely.
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-- Your code goes here
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```
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#### Exercise `<-trans-revisited` (practice) {name=less-trans-revisited}
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#### Exercise `<-trans-revisited` (practice) {#less-trans-revisited}
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Give an alternative proof that strict inequality is transitive,
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using the relation between strict inequality and inequality and
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@ -749,7 +749,7 @@ evidence that the first number is odd. If it is because it is the
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successor of an even number, then the result is odd because it is the
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successor of the sum of two even numbers, which is even.
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#### Exercise `o+o≡e` (stretch) {name=odd-plus-odd}
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#### Exercise `o+o≡e` (stretch) {#odd-plus-odd}
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Show that the sum of two odd numbers is even.
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@ -757,7 +757,7 @@ Show that the sum of two odd numbers is even.
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-- Your code goes here
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```
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#### Exercise `Bin-predicates` (stretch) {name=Bin-predicates}
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#### Exercise `Bin-predicates` (stretch) {#Bin-predicates}
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Recall that
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Exercise [Bin](/Naturals/#Bin)
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|
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@ -32,7 +32,7 @@ Chapter [Lambda](/Lambda/),
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and from it we compute an intrinsically-typed term, in the style of
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Chapter [DeBruijn](/DeBruijn/).
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## Introduction: Inference rules as algorithms {name=algorithms}
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## Introduction: Inference rules as algorithms {#algorithms}
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In the calculus we have considered so far, a term may have more than
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one type. For example,
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|
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@ -470,7 +470,7 @@ the equality test in the application rule in the first
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[section](/Inference/#algorithms).
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#### Exercise `bidirectional-mul` (recommended) {name=bidirectional-mul}
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#### Exercise `bidirectional-mul` (recommended) {#bidirectional-mul}
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Rewrite your definition of multiplication from
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Chapter [Lambda](/Lambda/), decorated to support inference.
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@ -480,7 +480,7 @@ Chapter [Lambda](/Lambda/), decorated to support inference.
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```
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||||
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#### Exercise `bidirectional-products` (recommended) {name=bidirectional-products}
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#### Exercise `bidirectional-products` (recommended) {#bidirectional-products}
|
||||
|
||||
Extend the bidirectional type rules to include products from
|
||||
Chapter [More](/More/).
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||||
|
|
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@ -213,7 +213,7 @@ definition may use `plusᶜ` as defined earlier (or may not
|
|||
```
|
||||
|
||||
|
||||
#### Exercise `primed` (stretch) {name=primed}
|
||||
#### Exercise `primed` (stretch) {#primed}
|
||||
|
||||
Some people find it annoying to write `` ` "x" `` instead of `x`.
|
||||
We can make examples with lambda terms slightly easier to write
|
||||
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|
@ -1201,7 +1201,7 @@ the three places where a bound variable is introduced.
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|||
The rules are deterministic, in that at most one rule applies to every term.
|
||||
|
||||
|
||||
### Example type derivations {name=derivation}
|
||||
### Example type derivations {#derivation}
|
||||
|
||||
Type derivations correspond to trees. In informal notation, here
|
||||
is a type derivation for the Church numeral two,
|
||||
|
|
|
|||
|
|
@ -147,7 +147,7 @@ Here `M †` is the translation of term `M` from a calculus with the
|
|||
construct to a calculus without the construct.
|
||||
|
||||
|
||||
## Products {name=products}
|
||||
## Products {#products}
|
||||
|
||||
### Syntax
|
||||
|
||||
|
|
@ -285,7 +285,7 @@ We can also translate back the other way:
|
|||
(`proj₁ L) ‡ = case× (L ‡) [⟨ x , y ⟩⇒ x ]
|
||||
(`proj₂ L) ‡ = case× (L ‡) [⟨ x , y ⟩⇒ y ]
|
||||
|
||||
## Sums {name=sums}
|
||||
## Sums {#sums}
|
||||
|
||||
### Syntax
|
||||
|
||||
|
|
|
|||
|
|
@ -879,7 +879,7 @@ typed (C-suc c) = ⊢suc (typed c)
|
|||
typed (C-rcd ⊢Ms dks As<:Bs) = ⊢<: (⊢rcd ⊢Ms dks) As<:Bs
|
||||
```
|
||||
|
||||
## Progress <a name="subtyping-progress"></a>
|
||||
## Progress <a #"subtyping-progress"></a>
|
||||
|
||||
The Progress theorem states that a well-typed term may either take a
|
||||
reduction step or it is already a value. The proof of Progress is like
|
||||
|
|
@ -952,7 +952,7 @@ progress (⊢<: {A = A}{B} ⊢M A<:B) = progress ⊢M
|
|||
* Case `⊢<:`: we invoke the induction hypothesis on sub-derivation of `Γ ⊢ M ⦂ A`.
|
||||
|
||||
|
||||
## Preservation <a name="subtyping-preservation"></a>
|
||||
## Preservation <a #"subtyping-preservation"></a>
|
||||
|
||||
In this section we prove that when a well-typed term takes a reduction
|
||||
step, the result is another well-typed term with the same type.
|
||||
|
|
|
|||
Loading…
Reference in a new issue