[fix] zero handling

src/num.typ

@@ -34,6 +34,12 @@
 
 // Process the exponent with its various modes mode
 #let process-exponent(info, exponent) = {
+
+  if (info.int + info.frac).trim("0") == "" {
+    // Add no exponent if number is 0
+    return info
+  }
+
   let new-exponent = if type(exponent) == dictionary {
     assert(
       "fixed" in exponent or "sci" in exponent,

src/rounding.typ

@@ -98,15 +98,18 @@
 /// 
 /// The result is never negative. 
 #let get-rounding-digit(int, frac, mode, precision) = {
-  let round-digit = precision + if mode == "places" {
-    int.len()
+  if mode == "places" {
+    precision + int.len()
   } else if mode == "figures" {
-    count-leading-zeros(int + frac)
+    if (int + frac).trim("0") == "" {
+      int.len()
+    } else {
+      precision + count-leading-zeros(int + frac)
+    }
   }
-
-  calc.max(round-digit)
 }
 
+
 /// Pads a decimal number to given precision with given rounding mode. 
 /// Examples with `pad: true`:
 /// - `62.1` (`"62", "1"`), `mode: "places", precision: 2`

tests/num/engineering/ref.typ

@@ -15,4 +15,9 @@ $10×10^(-3)$ \
 $1×10^(-3)$ \
 $100×10^(-6)$ \
 $10×10^(-6)$ \
-$1×10^(-6)$ \
+$1×10^(-6)$ \
+
+#pagebreak()
+
+$0$ \
+$0×10^2$ \

tests/num/engineering/test.typ

@@ -19,3 +19,8 @@
 #num(exponent: "eng")[.0001] \
 #num(exponent: "eng")[.00001] \
 #num(exponent: "eng")[1e-6] \
+
+#pagebreak()
+
+#num(exponent: "eng")[0] \
+#num(exponent: "eng")[0e2] \ // it's okay that the exponent is now 2

tests/num/fixed/ref.typ

@@ -7,4 +7,5 @@ $0.1234×10^1$ \
 $1000×10^1$ \
 $0.001×10^(-1)$ \
 $(0.2 plus.minus 0.1)×10^1$ \
-$(0.2 plus.minus 0.1)×10^2$ 
+$(0.2 plus.minus 0.1)×10^2$ \
+$0.00$ \

tests/num/fixed/test.typ

@@ -11,3 +11,4 @@
 #num(exponent: (fixed: -1))[1e-4] \
 #num(exponent: (fixed: 1))[2+-1] \
 #num(exponent: (fixed: 2))[2+-1e1] \
+#num(exponent: (fixed: 2))[0.00] \

tests/num/scientific/ref.typ

@@ -1,7 +1,7 @@
 #set page(width: auto, height: auto, margin: .5em)
 
 $1.23×10^2$ \
-$1.2×10^11$
+$1.2×10^11$ \
 
 #pagebreak()
 
@@ -16,3 +16,9 @@ $120$ \
 $1.200×10^3$ \
 $0.001$ \
 $1×10^(-4)$ \
+
+#pagebreak()
+
+$0$ \
+$0×10^4$ \
+$0.00$ \

tests/num/scientific/test.typ

@@ -19,3 +19,9 @@
 #num(exponent: (sci: (-4, 3)))[1200] \
 #num(exponent: (sci: (-4, 3)))[.001] \
 #num(exponent: (sci: (-4, 3)))[.0001] \
+
+#pagebreak()
+
+#num(exponent: "sci")[0] \
+#num(exponent: "sci")[0e4] \
+#num(exponent: "sci")[0.00] \

tests/num/trim-zeros/.gitignore

@@ -0,0 +1,5 @@
+# generated by tytanic, do not edit
+
+/diff/
+/out/
+/ref/

tests/rounding/ref.typ

@@ -0,0 +1,14 @@
+
+#set page(width: auto, height: auto, margin: .5em)
+
+
+$0.000$ \
+$0.000$ \
+$0$ \
+$0.000$ \
+
+#pagebreak()
+
+$423.4×10^2$ \
+$4.2×10^4$ \
+$42×10^3$ \

tests/rounding/test.typ

@@ -1,4 +1,5 @@
 #import "/src/rounding.typ": *
+#import "/src/zero.typ": num
 
 
 
@@ -258,3 +259,44 @@
   ),
   ("1", "23", (("", "04"), ("", "30"))),
 )
+#assert.eq(
+  round(
+    "0",
+    "",
+    precision: 2,
+    mode: "places",
+  ),
+  ("", "00", none),
+)
+
+#assert.eq(
+  round(
+    "0",
+    "",
+    precision: 2,
+    mode: "figures",
+  ),
+  ("", "", none),
+)
+
+
+
+
+
+
+#set page(width: auto, height: auto, margin: .5em)
+
+// Rounding zero
+#num(round: (precision: 3, mode: "places"))[0] \
+#num(round: (precision: 3, mode: "places"))[0.0] \
+#num(round: (precision: 3, mode: "figures"))[0] \
+#num(round: (precision: 3, mode: "places"), exponent: "sci")[0.0]
+
+#pagebreak()
+
+// Rounding affects displayed digits, (after the exponent is applied)
+#num(round: (precision: 1), exponent: (fixed: 2))[42.34e3] \
+#num(round: (precision: 1), exponent: "sci")[42.34e3] \
+#num(round: (precision: 2, mode: "figures"), exponent: "eng")[42.34e3] \
+
+