pprint WIP. #76

Author: eigenhombre

pprint.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+func pprint(s Sexpr) string {
+	c, ok := s.(*ConsCell)
+	if !ok {
+		return s.String()
+	}
+	return pprintCons(c, 0)
+}
+
+func pprintCons(c *ConsCell, indent int) string {
+	fmt.Println("indent:", indent)
+	firstTry := c.String()
+	if len(firstTry)+indent < 80 {
+		return c.String()
+	}
+	indentStr := strings.Repeat(" ", indent+1)
+	head := c.car.String()
+	ret := "("
+	for c != Nil {
+		if c.cdr == Nil {
+			ret += head
+			break
+		}
+		ret += head + "\n" + indentStr
+		c = c.cdr.(*ConsCell)
+		head = c.car.String()
+	}
+	return ret + ")"
+}

pprint_test.go

@@ -0,0 +1,149 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestPprint(t *testing.T) {
+	var tests = []struct {
+		example string
+	}{
+		{"1"},
+		{"(1 2 3)"},
+		{"(0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26)"},
+		{`(0
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+ 10
+ 11
+ 12
+ 13
+ 14
+ 15
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+ 92
+ 93
+ 94
+ 95
+ 96
+ 97
+ 98
+ 99)`},
+		{"(snuffleupagus snuffleupagus snuffleupagus)"},
+		{`(snuffleupagus
+ snuffleupagus
+ snuffleupagus
+ snuffleupagus
+ snuffleupagus
+ snuffleupagus
+ snuffleupagus
+ snuffleupagus
+ snuffleupagus
+ snuffleupagus)`},
+		{"(f snuffleupagus snuffleupagus snuffleupagus)"},
+		{`(f snuffleupagus
+   snuffleupagus
+   snuffleupagus
+   snuffleupagus
+   snuffleupagus
+   snuffleupagus
+   snuffleupagus
+   snuffleupagus
+   snuffleupagus
+   snuffleupagus)`},
+		{"(defn inc (x) (+ x 1))"},
+	}
+	for _, test := range tests {
+		s, err := lexAndParse([]string{test.example})
+		if err != nil {
+			t.Errorf("Testpprint: lexAndParse(%q) returned error: %v", test.example, err)
+		}
+		if pprint(s[0]) != test.example {
+			t.Errorf("%s != %s: FAIL", s[0], test.example)
+		} else {
+			t.Logf("%q == %q: OK", s[0], test.example)
+		}
+	}
+}