Add examples testing

Author: antonmedv

test/examples/examples_test.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"flag"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/expr-lang/expr"
+	"github.com/expr-lang/expr/internal/testify/require"
+)
+
+func TestExamples(t *testing.T) {
+	flag.Parse()
+
+	b, err := os.ReadFile("../../testdata/examples.md")
+	require.NoError(t, err)
+	examples := extractCodeBlocks(string(b))
+
+	for _, line := range examples {
+		line := line
+		t.Run(line, func(t *testing.T) {
+			program, err := expr.Compile(line, expr.Env(nil))
+			require.NoError(t, err)
+
+			_, err = expr.Run(program, nil)
+			require.NoError(t, err)
+		})
+	}
+}
+
+func extractCodeBlocks(markdown string) []string {
+	var blocks []string
+	var currentBlock []string
+	inBlock := false
+
+	lines := strings.Split(markdown, "\n")
+	for _, line := range lines {
+		trimmed := strings.TrimSpace(line)
+		if strings.HasPrefix(trimmed, "```") {
+			if inBlock {
+				blocks = append(blocks, strings.Join(currentBlock, "\n"))
+				currentBlock = nil
+				inBlock = false
+			} else {
+				inBlock = true
+			}
+			continue
+		}
+		if inBlock {
+			currentBlock = append(currentBlock, line)
+		}
+	}
+	return blocks
+}

test/gen/gen_test.go

@@ -16,7 +16,7 @@ var updateFlag = flag.Bool("update", false, "Drop failing lines from examples.tx
 func TestGenerated(t *testing.T) {
 	flag.Parse()
 
-	b, err := os.ReadFile("../../testdata/examples.txt")
+	b, err := os.ReadFile("../../testdata/generated.txt")
 	require.NoError(t, err)
 
 	examples := strings.TrimSpace(string(b))

testdata/examples.md

@@ -0,0 +1,129 @@
+# Examples
+
+Character Frequency Grouping
+
+```
+let char = "0";
+1..100000
+| map(string(#))
+| groupBy(split(#, char) | len() - 1)
+| toPairs()
+| map({{
+    count: #[0], 
+    len: len(#[1]), 
+    examples: [first(#[1]), last(#[1])],
+ }})
+| sortBy(.len, 'desc')
+```
+
+Log Filtering and Aggregation
+
+```
+let logs = [
+  {timestamp: date("2023-08-14 08:30:00"), message: "User logged in", level: "info"},
+  {timestamp: date("2023-08-14 09:00:00"), message: "Error processing payment", level: "error"},
+  {timestamp: date("2023-08-14 10:15:00"), message: "User logged out", level: "info"},
+  {timestamp: date("2023-08-14 11:00:00"), message: "Error connecting to database", level: "error"}
+];
+
+logs
+| filter(.level == "error")
+| map({{
+    time: string(.timestamp),
+    detail: .message
+ }})
+| sortBy(.time)
+```
+
+Financial Data Analysis and Summary
+
+```
+let accounts = [
+  {name: "Alice", balance: 1234.56, transactions: [100, -50, 200]},
+  {name: "Bob", balance: 2345.67, transactions: [-200, 300, -150]},
+  {name: "Charlie", balance: 3456.78, transactions: [400, -100, 50]}
+];
+
+{
+  totalBalance: sum(accounts, .balance),
+  averageBalance: mean(map(accounts, .balance)),
+  totalTransactions: reduce(accounts, #acc + len(.transactions), 0),
+  accounts: map(accounts, {{
+      name: .name,
+      final: .balance + sum(.transactions),
+      transactionCount: len(.transactions)
+  }})
+}
+```
+
+Bitwise Operations and Flags Decoding
+
+```
+let flags = [
+  {name: "read", value: 0b0001},
+  {name: "write", value: 0b0010},
+  {name: "execute", value: 0b0100},
+  {name: "admin", value: 0b1000}
+];
+
+let userPermissions = 0b1011;
+
+flags
+| filter(userPermissions | bitand(.value) != 0)
+| map(.name)
+```
+
+Nested Predicates with Optional Chaining
+
+```
+let users = [
+  {id: 1, name: "Alice", posts: [{title: "Hello World", content: "Short post"}, {title: "Another Post", content: "This is a bit longer post"}]},
+  {id: 2, name: "Bob", posts: nil},
+  {id: 3, name: "Charlie", posts: [{title: "Quick Update", content: "Update content"}]}
+];
+
+users
+| filter(
+    // Check if any post has content length greater than 10.
+    any(.posts ?? [], len(.content) > 10)
+  )
+| map({{name: .name, postCount: len(.posts ?? [])}})
+```
+
+String Manipulation and Validation
+
+```
+"  Apple, banana, Apple, orange, banana, kiwi "
+| trim()
+| split(",")
+| map(trim(#))
+| map(lower(#))
+| uniq()
+| sort()
+| join(", ")
+```
+
+Date Difference
+
+```
+let startDate = date("2023-01-01");
+let endDate = date("2023-12-31");
+let diff = endDate - startDate;
+{
+  daysBetween: diff.Hours() / 24,
+  hoursBetween: diff.Hours()
+}
+```
+
+Phone number filtering
+
+```
+let phone = filter(split("123-456-78901", ""), # in map(0..9, string(#)))[:10];
+join(concat(["("], phone[:3], [")"], phone[3:6], ["-"], phone[6:]))
+```
+
+Prime numbers
+
+```
+2..1000 | filter(let N = #; none(2..N-1, N % # == 0))
+```