journal: make numbers parsing more strict

- Hunt down adjacent punctuations with altering char.
- Add some tests dedicated to parsing amounts.

hledger-lib/Hledger/Read/Common.hs

@@ -531,7 +531,7 @@ numberp = do
   -- interspersed with periods, commas, or both
   -- ptrace "numberp"
   sign <- signp
-  parts <- some $ choice' [some digitChar, some $ char ',', some $ char '.']
+  parts <- some $ choice' [some digitChar, some $ oneOf ['.', ',']]
   dbg8 "numberp parsed" (sign,parts) `seq` return ()
 
   -- check the number is well-formed and identify the decimal point and digit

tests/journal/numbers.test

@@ -0,0 +1,112 @@
+# Simple case
+hledger bal -f - --no-total
+<<<
+2017/1/1
+	a   1,000.00 EUR
+	b  -1,000.00 EUR
+>>>
+        1,000.00 EUR  a
+       -1,000.00 EUR  b
+>>>2
+>>>=0
+
+# No digits before decimal sep
+hledger bal -f - --no-total
+<<<
+2017/1/1
+	a   .01 EUR
+	b
+>>>
+            0.01 EUR  a
+           -0.01 EUR  b
+>>>2
+>>>=0
+
+# No digits after decimal sep
+hledger bal -f - --no-total
+<<<
+2017/1/1
+	a   1. EUR
+	b
+>>>
+               1 EUR  a
+              -1 EUR  b
+>>>2
+>>>=0
+
+# No digits at all
+hledger bal -f -
+<<<
+2017/1/1
+	a   . EUR
+	b
+>>>
+>>>=1
+
+# Omitted decimals
+hledger bal -f -
+<<<
+2017/1/1
+	a   1,000 EUR
+	b  -1,000.00 EUR
+>>>
+>>>=1
+
+# Big prices
+hledger bal -f -  --no-total
+<<<
+2017/1/1
+	a   -1 BTC @ 24,840 UAH
+	b   24,840.00 UAH
+>>>
+>>>=1
+
+# adjacent punctuation chars
+hledger bal -f -
+<<<
+2017/1/1
+	a   1,,0,,0.0 EUR
+	b  -1..0..0,0 EUR
+>>>
+>>>=1
+
+# adjacent punctuation chars of different types
+hledger bal -f -
+<<<
+2017/1/1
+	a   1,0,.0 EUR
+	b  -1.0.,0 EUR
+>>>
+>>>=1
+
+# separator chars vary
+hledger bal -f -
+<<<
+2017/1/1
+	a   1.0,0.0,0 EUR
+	b  -1,0.0,0.0 EUR
+>>>
+>>>=1
+
+# number begins with a decimal char
+hledger bal -f -
+<<<
+2017/1/1
+	a   .1 EUR
+	b  -.1 EUR
+>>>
+             0.1 EUR  a
+            -0.1 EUR  b
+--------------------
+                   0
+>>>2
+>>>=0
+
+# number begins with a separator char
+hledger bal -f -
+<<<
+2017/1/1
+	a   ,100.0 EUR
+	b  -,100.0 EUR
+>>>
+>>>=1