split expression parser and evaluator

1 files changed, 174 insertions, 0 deletions

diff --git a/expr_test.go b/expr_test.go
new file mode 100644
index 0000000..e0bdf5b
--- /dev/null
+++ b/expr_test.go
@@ -0,0 +1,174 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseExpr(t *testing.T) {
+	for _, tc := range []struct {
+		in    string
+		val   Value
+		isErr bool
+	}{
+		{
+			in:  "foo",
+			val: literal("foo"),
+		},
+		{
+			in:  "(foo)",
+			val: literal("(foo)"),
+		},
+		{
+			in:  "{foo}",
+			val: literal("{foo}"),
+		},
+		{
+			in:  "$$",
+			val: literal("$"),
+		},
+		{
+			in:  "foo$$bar",
+			val: literal("foo$bar"),
+		},
+		{
+			in:  "$foo",
+			val: Expr{varref{varname: literal("f")}, literal("oo")},
+		},
+		{
+			in:  "$(foo)",
+			val: varref{varname: literal("foo")},
+		},
+		{
+			in: "$(foo:.c=.o)",
+			val: varsubst{
+				varname: literal("foo"),
+				pat:     literal(".c"),
+				subst:   literal(".o"),
+			},
+		},
+		{
+			in: "$(subst $(space),$(,),$(foo))/bar",
+			val: Expr{
+				&funcSubst{
+					fclosure: fclosure{
+						args: []Value{
+							varref{
+								varname: literal("space"),
+							},
+							varref{
+								varname: literal(","),
+							},
+							varref{
+								varname: literal("foo"),
+							},
+						},
+					},
+				},
+				literal("/bar"),
+			},
+		},
+		{
+			in: "$(subst $(space),$,,$(foo))",
+			val: &funcSubst{
+				fclosure: fclosure{
+					args: []Value{
+						varref{
+							varname: literal("space"),
+						},
+						varref{
+							varname: literal(""),
+						},
+						Expr{
+							literal(","),
+							varref{
+								varname: literal("foo"),
+							},
+						},
+					},
+				},
+			},
+		},
+		{
+			in: `$(shell echo '()')`,
+			val: &funcShell{
+				fclosure: fclosure{
+					args: []Value{
+						literal("echo '()'"),
+					},
+				},
+			},
+		},
+		{
+			in: `$(shell echo '()')`,
+			val: &funcShell{
+				fclosure: fclosure{
+					args: []Value{
+						literal("echo '()'"),
+					},
+				},
+			},
+		},
+		{
+			in: `$(shell echo ')')`,
+			val: Expr{
+				&funcShell{
+					fclosure: fclosure{
+						args: []Value{
+							literal("echo '"),
+						},
+					},
+				},
+				literal("')"),
+			},
+		},
+		{
+			in: `${shell echo ')'}`,
+			val: &funcShell{
+				fclosure: fclosure{
+					args: []Value{
+						literal("echo ')'"),
+					},
+				},
+			},
+		},
+		{
+			in: `${shell echo '}'}`,
+			val: Expr{
+				&funcShell{
+					fclosure: fclosure{
+						args: []Value{
+							literal("echo '"),
+						},
+					},
+				},
+				literal("'}"),
+			},
+		},
+		{
+			in: `$(shell make --version | ruby -n0e 'puts $$_[/Make (\d)/,1]')`,
+			val: &funcShell{
+				fclosure: fclosure{
+					args: []Value{
+						literal(`make --version | ruby -n0e 'puts $_[/Make (\d)/,1]'`),
+					},
+				},
+			},
+		},
+	} {
+		val, _, err := parseExpr([]byte(tc.in), nil)
+		if tc.isErr {
+			if err == nil {
+				t.Errorf(`parseExpr(%q)=_, _, nil; want error`, tc.in)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf(`parseExpr(%q)=_, _, %v; want nil error`, tc.in, err)
+			continue
+		}
+		if got, want := val, tc.val; !reflect.DeepEqual(got, want) {
+			t.Errorf("parseExpr(%[1]q)=%[2]q %#[2]v, _, _;\n want %[3]q %#[3]v, _, _", tc.in, got, want)
+		}
+	}
+}