add find-all-floats example

Author: alexflint

samples/find-all-floats/find-all-floats.go

@@ -0,0 +1,59 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/alexflint/go-restructure"
+)
+
+var src = `
+The US economy went through an economic downturn following the financial 
+crisis of 2007–08, with output as late as 2013 still below potential
+according to the Congressional Budget Office.[57] The economy, however,
+began to recover in the second half of 2009, and as of November 2015,
+unemployment had declined from a high of 10% to 5%; the government's
+broader U-6 unemployment rate, which includes the part-time underemployed,
+was 9.8% (it had reached 16% in 2009).[13] At 11.3%, the U.S. has one of
+the lowest labor union participation rates in the OECD.[58] Households
+living on less than $2 per day before government benefits, doubled from
+1996 levels to 1.5 million households in 2011, including 2.8 million
+children.[59] The gap in income between rich and poor is greater in the
+United States than in any other developed country.[60] Total public and
+private debt was $50 trillion at the end of the first quarter of 2010,
+or 3.5 times GDP.[61] In December 2014, public debt was slightly more
+than 100% of GDP.[62] Domestic financial assets totaled $131 trillion
+and domestic financial liabilities totaled $106 trillion.[63]
+`
+
+var floatRegexp = restructure.MustCompile(Float{}, restructure.Options{})
+
+// Matches "123", "1.23", "1.23e-4", "-12.3E+5", ".123"
+type Float struct {
+	Begin    restructure.Pos
+	Sign     *Sign     `?`
+	Whole    string    `[0-9]*`
+	Period   struct{}  `\.?`
+	Frac     string    `[0-9]+`
+	Exponent *Exponent `?`
+	End      restructure.Pos
+}
+
+// Matches "+" or "-"
+type Sign struct {
+	Ch string `[+-]`
+}
+
+// Matches "e+4", "E6", "e-03"
+type Exponent struct {
+	_    struct{} `[eE]`
+	Sign *Sign    `?`
+	Num  string   `[0-9]+`
+}
+
+func main() {
+	var floats []Float
+	floatRegexp.FindAll(&floats, src, -1)
+	for _, f := range floats {
+		fmt.Println(src[f.Begin:f.End])
+	}
+}