If expressions 🔀

6 files changed, 102 insertions, 31 deletions

diff --git a/tests/lang/ref/if.png b/tests/lang/ref/if.png
new file mode 100644
index 00000000..da99e185
--- /dev/null
+++ b/tests/lang/ref/if.png
diff --git a/tests/lang/ref/let.png b/tests/lang/ref/let.png
index d9833391..4b8a1131 100644
--- a/tests/lang/ref/let.png
+++ b/tests/lang/ref/let.png
diff --git a/tests/lang/typ/bracket-call.typ b/tests/lang/typ/bracket-call.typ
index 7bbaeac1..4b92a4b8 100644
--- a/tests/lang/typ/bracket-call.typ
+++ b/tests/lang/typ/bracket-call.typ
@@ -70,7 +70,7 @@
 
 ---
 // Ref: false
-// Error: 2:2-2:3 a value of type string is not callable
+// Error: 2:2-2:3 expected function, found string
 #let x = "string"
 [x]
 
diff --git a/tests/lang/typ/headings.typ b/tests/lang/typ/headings.typ
index 765d0377..e63574ca 100644
--- a/tests/lang/typ/headings.typ
+++ b/tests/lang/typ/headings.typ
@@ -6,7 +6,7 @@
 ###### Six
 
 // Too many hashtags.
-// Warning: 1:1-1:8 section depth should not exceed 6
+// Warning: 1:1-1:8 should not exceed depth 6
 ####### Seven
 
 ---
diff --git a/tests/lang/typ/if.typ b/tests/lang/typ/if.typ
new file mode 100644
index 00000000..5f4c986a
--- /dev/null
+++ b/tests/lang/typ/if.typ
@@ -0,0 +1,66 @@
+#let x = true
+
+// The two different bodies.
+#if true [_1_,] #if x {"2"}
+
+// Braced condition is fine.
+#if {true} {"3"}
+
+// Newline between body and else-clause.
+#if false []
+#else [4]
+
+// Multiline (condition needs parens because it's terminated by the line break,
+// just like the right-hand side of a let-binding).
+#if
+    x
+{
+    "Fi" + "ve"
+}
+
+// Spacing is somewhat delicated. We only want to have spacing in the output if
+// there was whitespace before/after the full if-else statement. In particular,
+// spacing after a simple if should be retained, but spacing between the first
+// body and the else should be ignored.
+a#if true[b]c \
+a#if true[b] c \
+a #if true{"b"}c \
+a #if true{"b"} c \
+a#if false [?] #else [b]c \
+a#if true {"b"} #else {"?"} c \
+
+// Body not evaluated at all if condition is false.
+#if false { dont-care-about-undefined-variables }
+
+---
+#let x = true
+
+// Needs condition.
+// Error: 1:6-1:7 expected expression, found closing brace
+a#if }
+
+// Needs if-body.
+// Error: 2:7-2:7 expected body
+// Error: 1:16-1:16 expected body
+a#if x b#if (x)c
+
+// Needs if-body expression.
+// Error: 1:12-1:12 expected expression
+a#if true {}
+
+// Needs else-body.
+// Error: 1:20-1:20 expected body
+a#if true [b] #else c
+
+// Lone else.
+// Error: 2:1-2:6 unexpected else keyword
+// Error: 1:8-1:8 expected function name
+#else []
+
+// Condition must be boolean. If it isn't, neither branch is evaluated.
+// Error: 1:5-1:14 expected boolean, found string
+#if "a" + "b" { "nope" } #else { "nope" }
+
+// No coercing from empty array or or stuff like that.
+// Error: 1:5-1:7 expected boolean, found array
+#if () { "nope" } #else { "nope" }
diff --git a/tests/lang/typ/let.typ b/tests/lang/typ/let.typ
index 28fc6649..3f8f5e0f 100644
--- a/tests/lang/typ/let.typ
+++ b/tests/lang/typ/let.typ
@@ -1,5 +1,3 @@
-// Ref: false
-
 // Automatically initialized with `none`.
 #let x
 [eq x, none]
@@ -8,46 +6,53 @@
 #let y = 1
 [eq y, 1]
 
+// Initialize with template, not terminated by semicolon in template.
+#let v = [Hello; there]
+
+// Not terminated by line break due to parens.
+#let x = (
+    1,
+    2,
+    3,
+)
+[eq x, (1, 2, 3)]
+
 // Multiple bindings in one line.
 #let x = "a"; #let y = "b"; [eq x + y, "ab"]
 
-// No name.
+// Invalid name.
 // Error: 1:6-1:7 expected identifier, found integer
 #let 1
 
----
+// Terminated by end of line before binding name.
+// Error: 1:5-1:5 expected identifier
+#let
+x = 5
+
+// No name at all.
+// Error: 1:11-1:11 expected identifier
+The Fi#let;rst
+
 // Terminated with just a line break.
 #let v = "a"
-First
-[eq v, "a"]
-
-// Terminated with just a semicolon.
-#let v = "a"; Second
-[eq v, "a"]
+The Second [eq v, "a"]
 
 // Terminated with semicolon + line break.
 #let v = "a";
-Third
-[eq v, "a"]
+The Third [eq v, "a"]
+
+// Terminated with just a semicolon.
+The#let v = "a"; Fourth [eq v, "a"]
 
 // Terminated by semicolon even though we are in a paren group.
-// Error: 2:22-2:22 expected expression
-// Error: 1:22-1:22 expected closing paren
-#let array = (1, 2 + ;Fourth
-[eq array, (1, 2)]
+// Error: 2:25-2:25 expected expression
+// Error: 1:25-1:25 expected closing paren
+The#let array = (1, 2 + ;Fifth [eq array, (1, 2)]
 
 // Not terminated.
-// Error: 1:14-1:20 expected semicolon or line break, found identifier
-#let v = "a" Unseen Fifth
-[eq v, "a"]
+// Error: 1:16-1:16 expected semicolon or line break
+The#let v = "a"Sixth [eq v, "a"]
 
-// Not terminated by semicolon in template.
-#let v = [Hello; there]
-
-// Not terminated by line break due to parens.
-#let x = (
-    1,
-    2,
-    3,
-)
-[eq x, (1, 2, 3)]
+// Not terminated.
+// Error: 1:16-1:16 expected semicolon or line break
+The#let v = "a" [eq v, "a"] Seventh