mirror of
https://github.com/gopl-zh/gopl-zh.github.com.git
synced 2024-12-01 10:38:59 +00:00
114 lines
2.4 KiB
Go
114 lines
2.4 KiB
Go
// Copyright © 2016 Alan A. A. Donovan & Brian W. Kernighan.
|
|
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
|
|
|
|
package eval
|
|
|
|
import (
|
|
"fmt"
|
|
"math"
|
|
"testing"
|
|
)
|
|
|
|
//!+Eval
|
|
func TestEval(t *testing.T) {
|
|
tests := []struct {
|
|
expr string
|
|
env Env
|
|
want string
|
|
}{
|
|
{"sqrt(A / pi)", Env{"A": 87616, "pi": math.Pi}, "167"},
|
|
{"pow(x, 3) + pow(y, 3)", Env{"x": 12, "y": 1}, "1729"},
|
|
{"pow(x, 3) + pow(y, 3)", Env{"x": 9, "y": 10}, "1729"},
|
|
{"5 / 9 * (F - 32)", Env{"F": -40}, "-40"},
|
|
{"5 / 9 * (F - 32)", Env{"F": 32}, "0"},
|
|
{"5 / 9 * (F - 32)", Env{"F": 212}, "100"},
|
|
//!-Eval
|
|
// additional tests that don't appear in the book
|
|
{"-1 + -x", Env{"x": 1}, "-2"},
|
|
{"-1 - x", Env{"x": 1}, "-2"},
|
|
//!+Eval
|
|
}
|
|
var prevExpr string
|
|
for _, test := range tests {
|
|
// Print expr only when it changes.
|
|
if test.expr != prevExpr {
|
|
fmt.Printf("\n%s\n", test.expr)
|
|
prevExpr = test.expr
|
|
}
|
|
expr, err := Parse(test.expr)
|
|
if err != nil {
|
|
t.Error(err) // parse error
|
|
continue
|
|
}
|
|
got := fmt.Sprintf("%.6g", expr.Eval(test.env))
|
|
fmt.Printf("\t%v => %s\n", test.env, got)
|
|
if got != test.want {
|
|
t.Errorf("%s.Eval() in %v = %q, want %q\n",
|
|
test.expr, test.env, got, test.want)
|
|
}
|
|
}
|
|
}
|
|
|
|
//!-Eval
|
|
|
|
/*
|
|
//!+output
|
|
sqrt(A / pi)
|
|
map[A:87616 pi:3.141592653589793] => 167
|
|
|
|
pow(x, 3) + pow(y, 3)
|
|
map[x:12 y:1] => 1729
|
|
map[x:9 y:10] => 1729
|
|
|
|
5 / 9 * (F - 32)
|
|
map[F:-40] => -40
|
|
map[F:32] => 0
|
|
map[F:212] => 100
|
|
//!-output
|
|
|
|
// Additional outputs that don't appear in the book.
|
|
|
|
-1 - x
|
|
map[x:1] => -2
|
|
|
|
-1 + -x
|
|
map[x:1] => -2
|
|
*/
|
|
|
|
func TestErrors(t *testing.T) {
|
|
for _, test := range []struct{ expr, wantErr string }{
|
|
{"x % 2", "unexpected '%'"},
|
|
{"math.Pi", "unexpected '.'"},
|
|
{"!true", "unexpected '!'"},
|
|
{`"hello"`, "unexpected '\"'"},
|
|
{"log(10)", `unknown function "log"`},
|
|
{"sqrt(1, 2)", "call to sqrt has 2 args, want 1"},
|
|
} {
|
|
expr, err := Parse(test.expr)
|
|
if err == nil {
|
|
vars := make(map[Var]bool)
|
|
err = expr.Check(vars)
|
|
if err == nil {
|
|
t.Errorf("unexpected success: %s", test.expr)
|
|
continue
|
|
}
|
|
}
|
|
fmt.Printf("%-20s%v\n", test.expr, err) // (for book)
|
|
if err.Error() != test.wantErr {
|
|
t.Errorf("got error %s, want %s", err, test.wantErr)
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
//!+errors
|
|
x % 2 unexpected '%'
|
|
math.Pi unexpected '.'
|
|
!true unexpected '!'
|
|
"hello" unexpected '"'
|
|
|
|
log(10) unknown function "log"
|
|
sqrt(1, 2) call to sqrt has 2 args, want 1
|
|
//!-errors
|
|
*/
|