merge

.travis.yml

@@ -36,7 +36,7 @@ before_install:
 - make travis-setup
 
 script:
-- curl -L https://raw.githubusercontent.com/MestreLion/git-tools/master/git-restore-mtime | python
+- travis_retry curl -L https://raw.githubusercontent.com/plfa/git-tools/master/git-restore-mtime | python
 - agda --version
 - acknowledgements --version
 - make test-offline # disable to only build cache

README.md

@@ -58,8 +58,23 @@ but Aquamacs users might need to move their startup settings to the Preferences.
 
 If you're having trouble typing the Unicode characters into Emacs, the end of
 each chapter should provide a list of the unicode characters introduced in that
-chapter. For a full list of supported characters, see
-[agda-input.el](https://github.com/agda/agda/blob/master/src/data/emacs-mode/agda-input.el#L194).
+chapter.
+
+`agda-mode` and emacs have a number of useful commands.
+Two of them are especially useful when you solve exercises.
+
+For a full list of supported characters, use `agda-input-show-translations` with:
+
+    M-x agda-input-show-translations
+
+All the supported characters in `agda-mode` are shown.
+
+If you want to know how you input a specific Unicode character in agda file,
+move the cursor onto the character and type the following command:
+
+    M-x quail-show-key
+
+You'll see the key sequence of the character in mini buffer.
 
 
 ## Using `agda-mode`

beta.md

@@ -64,7 +64,8 @@ Pull requests are encouraged.
 
   - Courses taught from the textbook:
     * Philip Wadler, University of Edinburgh,
-      [2018]({{ site.baseurl }}/TSPL/2018/)
+      [2018]({{ site.baseurl }}/TSPL/2018/),
+	  [2019]({{ site.baseurl }}/TSPL/2019/)
     * David Darais, University of Vermont,
       [2018](http://david.darais.com/courses/fa2018-cs295A/)
     * John Leo, Google Seattle, 2018--2019
@@ -72,6 +73,8 @@ Pull requests are encouraged.
       [2019]({{ site.baseurl }}/PUC/2019/)
     * Prabhakar Ragde, University of Waterloo,
       [2019](https://cs.uwaterloo.ca/~plragde/842/)
+    * Jeremy Siek, Indiana University,
+	  [2020](https://jsiek.github.io/B522-PL-Foundations/)
   - A paper describing the book appeared in [SBMF][sbmf].
 
 [wen]: https://wenkokke.github.io

courses/tspl/send_marks.sh

@@ -6,7 +6,7 @@
 #
 # This script assumes the following folder structure:
 #
-#   $DIR/sXXXXXXX/cw$CW/$FILE
+#   $DIR/sXXXXXXX/$CW/$FILE
 #
 # The variable DIR refers to the directory passed in as an argument to the
 # script. The variable XXXXXXX refers to the student ID, and it is assumed
@@ -14,9 +14,9 @@
 #
 #   sXXXXXXX@sms.ed.ac.uk
 #
-# is a valid email address. The variable $CW refers to the number for of the
-# coursework of which the students are meant to be notified. The directory
-# DIR/sXXXXXXX/cwY/ should only contain a single file, which should be
+# is a valid email address. The variable $CW refers to the coursework
+# of which the students are meant to be notified (e.g., cw1). The directory
+# DIR/sXXXXXXX/$CW/ should only contain a single file, which should be
 # specified using the FILE parameter.
 #
 # Usage:
@@ -32,12 +32,12 @@ shift
 FILE="$1"
 shift
 
-for ATTACHMENT in "${DIR%/}/s"*"/cw$CW/$FILE"; do
+for ATTACHMENT in "${DIR%/}/s"*"/$CW/$FILE"; do
     SUBJ="Mark for coursework $CW"
     BODY=""
     SID=$(echo "$ATTACHMENT" | sed 's|.*/\(s[0-9]\{7\}\)/.*|\1|')
     ADDR="$SID@sms.ed.ac.uk"
-    CMD="echo \"$BODY\" | mail -s \"$SUBJ\" -a \"$ATTACHMENT\" \"$ADDR\""
+    CMD="echo \"$BODY\" | mail -c wadler@inf.ed.ac.uk -s \"$SUBJ\" -a \"$ATTACHMENT\" \"$ADDR\""
     echo "You are about to run the following command:"
     echo -e "\n$CMD\n"
     read -p "Are you sure? " -n 1 -r

index.md

@@ -61,9 +61,15 @@ Pull requests are encouraged.
     * Adrian King,
       San Francisco Types, Theorems, and Programming Languages Meetup
       [2019-20](http://meet.meetup.com/wf/click?upn=ZDzXt-2B-2BZmzYir6Bq5X7vEQ2iNYdgjN9-2FU9nWKp99AU8rZjrncUsSYODqOGn6kV-2BqW71oirCo-2Bk8O1q2FtDFhYZR-2B737CPhNWBjt58LuSRC-2BWTj61VZCHquysW8z7dVtQWxB5Sorl3chjZLDptP70L7aBZL14FTERnKJcRQdrMtc-3D_IqHN4t3hH47BvE1Cz0BakIxV4odHudhr6IVs-2Fzslmv-2FBuORsh-2FwQmOxMBdyMHsSBndQDQmt47hobqsLp-2Bm04Y9LwgV66MGyucsd0I9EgDEUB-2FjzdtSgRv-2Fxng8Pgsa3AZIEYILOhLpQ5ige5VFYTEHVN1pEqnujCHovmTxJkqAK9H-2BIL15-2FPxx97RfHcz7M30YNyqp6TOYfgTxyUHc6lufYKFA75Y7MV6MeDJMxw9-2FYUxR6CEjdoagQBmaGkBVzN)	  
+    * Jeremy Siek, Indiana University,
+	  [2020](https://jsiek.github.io/B522-PL-Foundations/)
   - A paper describing the book appeared in [SBMF][sbmf].
-
+  - A notebook version of the textbook
+    is available at [NextJournal][nextjournal].
+    It lets you edit and execute the book via a web interface.
+	
 [wen]: https://github.com/wenkokke
 [phil]: https://homepages.inf.ed.ac.uk/wadler/
 [GitHub]: https://github.com/plfa/plfa.github.io/
 [sbmf]: https://homepages.inf.ed.ac.uk/wadler/topics/agda.html#sbmf
+[nextjournal]: https://nextjournal.com/plfa/ToC

src/plfa/part1/Lists.lagda.md

@@ -353,6 +353,7 @@ reverse of the second appended to the reverse of the first:
 
     reverse (xs ++ ys) ≡ reverse ys ++ reverse xs
 
+
 #### Exercise `reverse-involutive` (recommended)
 
 A function is an _involution_ if when applied twice it acts

src/plfa/part1/Naturals.lagda.md

@@ -965,8 +965,8 @@ After typing `\r`, one can access the many available arrows by using
 the left, right, up, and down keys to navigate.  The command remembers
 where you navigated to the last time, and starts with the same
 character next time.  The command `\l` works similarly for left arrows.
-
-In place of left, right, up, and down keys, one may also use control characters:
+In place of left, right, up, and down keys, one may also use control
+characters:
 
     C-b  left (backward one character)
     C-f  right (forward one character)
@@ -975,3 +975,18 @@ In place of left, right, up, and down keys, one may also use control characters:
 
 We write `C-b` to stand for control-b, and similarly.  One can also navigate
 left and right by typing the digits that appear in the displayed list.
+
+For a full list of supported characters, use `agda-input-show-translations` with:
+
+    M-x agda-input-show-translations
+
+All the characters supported by `agda-mode` are shown. We write M-x to stand for
+typing `ESC` followed by `x`.
+
+If you want to know how you input a specific Unicode character in an agda file,
+move the cursor onto the character and use `quail-show-key` with:
+
+    M-x quail-show-key
+
+You'll see a key sequence of the character in mini buffer.
+If you run `M-x qualy-show-key` on say `∸`, you will see `\.-` for the character.

src/plfa/part2/Lambda.lagda.md

@@ -72,7 +72,7 @@ Terms have seven constructs. Three are for the core lambda calculus:
 Three are for the naturals:
 
   * Zero `` `zero ``
-  * Successor `` `suc ``
+  * Successor `` `suc M ``
   * Case `` case L [zero⇒ M |suc x ⇒ N ] ``
 
 And one is for recursion:
@@ -234,11 +234,11 @@ We intend to apply the function only when the first term is a variable, which we
 indicate by postulating a term `impossible` of the empty type `⊥`.  If we use
 C-c C-n to normalise the term
 
-  ƛ′ two ⇒ two
+    ƛ′ two ⇒ two
 
 Agda will return an answer warning us that the impossible has occurred:
 
-  ⊥-elim (plfa.part2.Lambda.impossible (`` `suc (`suc `zero)) (`suc (`suc `zero)) ``)
+    ⊥-elim (plfa.part2.Lambda.impossible (`` `suc (`suc `zero)) (`suc (`suc `zero)) ``)
 
 While postulating the impossible is a useful technique, it must be
 used with care, since such postulation could allow us to provide
@@ -1315,7 +1315,7 @@ there is at most one `A` such that the judgment holds:
 ```
 
 The typing relation `Γ ⊢ M ⦂ A` is not injective. For example, in any `Γ`
-the term `ƛ "x" ⇒ "x"` has type `A ⇒ A` for any type `A`.
+the term `` ƛ "x" ⇒ ` "x" `` has type `A ⇒ A` for any type `A`.
 
 ### Non-examples
 

src/plfa/part2/Properties.lagda.md

@@ -568,7 +568,7 @@ swap {Γ} {x} {y} {M} {A} {B} {C} x≢y ⊢M = rename ρ ⊢M
       --------------------------
     → Γ , x ⦂ A , y ⦂ B ∋ z ⦂ C
   ρ Z                   =  S x≢y Z
-  ρ (S y≢x Z)           =  Z
+  ρ (S z≢x Z)           =  Z
   ρ (S z≢x (S z≢y ∋z))  =  S z≢y (S z≢x ∋z)
 ```
 Here the renaming map takes a variable at the end into a variable one
@@ -742,8 +742,8 @@ Now that naming is resolved, let's unpack the first three cases:
 
         ∅ ⊢ V ⦂ B
         Γ , x ⦂ A , y ⦂ B ⊢ N ⦂ C
-        ------------------------------------
-        Γ , x ⦂ A , y ⦂ B ⊢ N [ y := V ] ⦂ C
+        ----------------------------
+        Γ , x ⦂ A ⊢ N [ y := V ] ⦂ C
 
     The typing rule for abstractions then yields the required conclusion.