Parsing negative numbers now returns negative values

Fixes tidyverse#308

NEWS.md

@@ -9,6 +9,8 @@
   than numeric vectors (#357, @jimhester).
 * Add `na` arguments to `parse_date()` `parse_time()` and `parse_datetime()`
   (#413, @jimhester).
+* Fix bug when parsing negative number returns a positive value (#308,
+  @jimhester).
 
 * Fix bug when detecting column types for single row files without headers
   (#333, @jimhester).

src/QiParsers.h

@@ -52,13 +52,15 @@ inline bool parseNumber(char decimalMark, char groupingMark, Iterator& first,
   double sum = 0, denom = 1;
   NumberState state = STATE_INIT;
   bool seenNumber = false;
+  double sign = 1.0;
 
   Iterator cur = first;
   for(; cur != last; ++cur) {
     switch(state) {
     case STATE_INIT:
       if (*cur == '-') {
         state = STATE_LHS;
+        sign = -1.0;
       } else if (*cur == decimalMark) {
         state = STATE_RHS;
       } else if (*cur >= '0' && *cur <= '9') {
@@ -100,14 +102,14 @@ inline bool parseNumber(char decimalMark, char groupingMark, Iterator& first,
       break;
     case STATE_FIN:
       last = cur++;
-      res = sum;
+      res = sign * sum;
       return seenNumber;
     }
   }
 
   // Hit the end of the string, so must be done
   last = cur;
-  res = sum;
+  res = sign * sum;
 
   // Only true if we saw a number and reached the end of the string without
   // finishing the number

tests/testthat/test-parsing-numeric.R

@@ -75,3 +75,11 @@ test_that("read_tsv passes on decimal_mark", {
   out <- read_tsv("x\n1,5", locale = es_MX)
   expect_equal(out$x, 1.5)
 })
+
+# Negative numbers -----------------------------------------------------------
+
+test_that("negative numbers return negative values", {
+  expect_equal(parse_number("-2"), -2)
+
+  expect_equal(parse_number("-100,000.00"), -100000)
+})