claude/add-table-rendering-41A3r

cmd/build.go

@@ -33,12 +33,21 @@ func Note(file, text string) error {
 
 // Exec appends a code block, executes it, and appends the output.
 // It returns the captured output, the process exit code, and any error.
+// If lang has a " {table}" suffix, the output is parsed as TSV and rendered
+// as a markdown table instead of a plain output fence.
 func Exec(file, lang, code, workdir string) (string, int, error) {
 	if _, err := os.Stat(file); err != nil {
 		return "", 1, fmt.Errorf("file not found: %s", file)
 	}
 
-	output, exitCode, err := execpkg.Run(lang, code, workdir)
+	// Detect {table} annotation and strip it for execution.
+	isTable := strings.HasSuffix(lang, " {table}")
+	runLang := lang
+	if isTable {
+		runLang = strings.TrimSuffix(lang, " {table}")
+	}
+
+	output, exitCode, err := execpkg.Run(runLang, code, workdir)
 	if err != nil {
 		return "", exitCode, fmt.Errorf("running code: %w", err)
 	}
@@ -48,17 +57,26 @@ func Exec(file, lang, code, workdir string) (string, int, error) {
 		return "", exitCode, err
 	}
 
-	codeBlock := markdown.CodeBlock{Lang: lang, Code: code}
-	outputBlock := markdown.OutputBlock{Content: output}
-	blocks = append(blocks, codeBlock, outputBlock)
+	codeBlock := markdown.CodeBlock{Lang: runLang, Code: code, IsTable: isTable}
+	var outputBlk markdown.Block
+	if isTable {
+		headers, rows, parseErr := execpkg.ParseTSV(output)
+		if parseErr != nil {
+			return output, exitCode, fmt.Errorf("parsing table output: %w", parseErr)
+		}
+		outputBlk = markdown.TableOutputBlock{Headers: headers, Rows: rows}
+	} else {
+		outputBlk = markdown.OutputBlock{Content: output}
+	}
+	blocks = append(blocks, codeBlock, outputBlk)
 
 	if err := writeBlocks(file, blocks); err != nil {
 		return output, exitCode, err
 	}
 
 	docID := documentID(blocks)
 	if docID != "" {
-		postSection(docID, "exec", []markdown.Block{codeBlock, outputBlock})
+		postSection(docID, "exec", []markdown.Block{codeBlock, outputBlk})
 	}
 
 	return output, exitCode, nil

cmd/build_test.go

@@ -348,6 +348,81 @@ func TestImageMarkdownRefEscapedBang(t *testing.T) {
 	}
 }
 
+func TestExecTable(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "demo.md")
+
+	if err := Init(file, "Test", "dev"); err != nil {
+		t.Fatal(err)
+	}
+
+	code := `printf 'name\tage\nAlice\t30\nBob\t25\n'`
+	output, exitCode, err := Exec(file, "bash {table}", code, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if exitCode != 0 {
+		t.Errorf("expected exit code 0, got %d", exitCode)
+	}
+	if output != "name\tage\nAlice\t30\nBob\t25\n" {
+		t.Errorf("unexpected output: %q", output)
+	}
+
+	content, err := os.ReadFile(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	s := string(content)
+	if !strings.Contains(s, "```bash {table}") {
+		t.Errorf("expected table code block in file, got: %s", s)
+	}
+	if !strings.Contains(s, "| name | age |") {
+		t.Errorf("expected table header in file, got: %s", s)
+	}
+	if !strings.Contains(s, "| Alice | 30 |") {
+		t.Errorf("expected table row in file, got: %s", s)
+	}
+	// Should NOT contain an output fence
+	if strings.Contains(s, "```output") {
+		t.Errorf("should not have output fence for table exec, got: %s", s)
+	}
+}
+
+func TestPopTableEntry(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "demo.md")
+
+	if err := Init(file, "Test", "dev"); err != nil {
+		t.Fatal(err)
+	}
+
+	code := `printf 'name\tage\nAlice\t30\n'`
+	if _, _, err := Exec(file, "bash {table}", code, ""); err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify table is in the file
+	content, _ := os.ReadFile(file)
+	if !strings.Contains(string(content), "| name | age |") {
+		t.Fatal("expected table in file before pop")
+	}
+
+	// Pop should remove both the code block and the table output
+	if err := Pop(file); err != nil {
+		t.Fatal(err)
+	}
+
+	content, _ = os.ReadFile(file)
+	s := string(content)
+	if strings.Contains(s, "{table}") {
+		t.Errorf("expected code block to be removed after pop, got: %s", s)
+	}
+	if strings.Contains(s, "| name | age |") {
+		t.Errorf("expected table to be removed after pop, got: %s", s)
+	}
+}
+
 func TestImageMarkdownRefBadPath(t *testing.T) {
 	dir := t.TempDir()
 	file := filepath.Join(dir, "demo.md")

cmd/extract.go

@@ -36,12 +36,18 @@ func Extract(file, outputFile string) ([]string, error) {
 			if b.IsImage {
 				commands = append(commands, fmt.Sprintf("showboat image %s %s", quotedTarget, shellQuote(b.Code)))
 			} else {
-				commands = append(commands, fmt.Sprintf("showboat exec %s %s %s", quotedTarget, b.Lang, shellQuote(b.Code)))
+				lang := b.Lang
+				if b.IsTable {
+					lang += " {table}"
+				}
+				commands = append(commands, fmt.Sprintf("showboat exec %s %s %s", quotedTarget, shellQuote(lang), shellQuote(b.Code)))
 			}
 		case markdown.OutputBlock:
 			// Skip: generated by running code blocks
 		case markdown.ImageOutputBlock:
 			// Skip: generated by running image scripts
+		case markdown.TableOutputBlock:
+			// Skip: generated by running table code blocks
 		}
 	}
 

cmd/extract_test.go

@@ -68,6 +68,32 @@ func TestExtractOutputOverride(t *testing.T) {
 	}
 }
 
+func TestExtractTable(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "demo.md")
+
+	if err := Init(file, "Test", "dev"); err != nil {
+		t.Fatal(err)
+	}
+	code := `printf 'name\tage\nAlice\t30\n'`
+	if _, _, err := Exec(file, "bash {table}", code, ""); err != nil {
+		t.Fatal(err)
+	}
+
+	commands, err := Extract(file, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(commands) != 2 {
+		t.Fatalf("expected 2 commands, got %d: %v", len(commands), commands)
+	}
+	// The exec command should include {table} in the language
+	if !strings.Contains(commands[1], "{table}") {
+		t.Errorf("expected exec command to include {table}, got: %s", commands[1])
+	}
+}
+
 func TestExtractShellQuote(t *testing.T) {
 	tests := []struct {
 		input    string

cmd/pop.go

@@ -32,7 +32,7 @@ func Pop(file string) error {
 	last := blocks[len(blocks)-1]
 
 	switch last.(type) {
-	case markdown.OutputBlock, markdown.ImageOutputBlock:
+	case markdown.OutputBlock, markdown.ImageOutputBlock, markdown.TableOutputBlock:
 		// Output blocks are always preceded by a code block — remove both.
 		if len(blocks) >= 2 {
 			blocks = blocks[:len(blocks)-2]

exec/table.go

@@ -0,0 +1,26 @@
+package exec
+
+import (
+	"fmt"
+	"strings"
+)
+
+// ParseTSV parses tab-separated output into headers and rows.
+// The first line is treated as the header row. Empty trailing lines are ignored.
+func ParseTSV(output string) ([]string, [][]string, error) {
+	lines := strings.Split(output, "\n")
+	// Remove empty trailing lines
+	for len(lines) > 0 && lines[len(lines)-1] == "" {
+		lines = lines[:len(lines)-1]
+	}
+	if len(lines) == 0 {
+		return nil, nil, fmt.Errorf("empty output: no header row found")
+	}
+
+	headers := strings.Split(lines[0], "\t")
+	var rows [][]string
+	for _, line := range lines[1:] {
+		rows = append(rows, strings.Split(line, "\t"))
+	}
+	return headers, rows, nil
+}

exec/table_test.go

@@ -0,0 +1,74 @@
+package exec
+
+import (
+	"testing"
+)
+
+func TestParseTSV(t *testing.T) {
+	input := "name\tage\nAlice\t30\nBob\t25\n"
+	headers, rows, err := ParseTSV(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(headers) != 2 || headers[0] != "name" || headers[1] != "age" {
+		t.Errorf("unexpected headers: %v", headers)
+	}
+	if len(rows) != 2 {
+		t.Fatalf("expected 2 rows, got %d", len(rows))
+	}
+	if rows[0][0] != "Alice" || rows[0][1] != "30" {
+		t.Errorf("unexpected row 0: %v", rows[0])
+	}
+	if rows[1][0] != "Bob" || rows[1][1] != "25" {
+		t.Errorf("unexpected row 1: %v", rows[1])
+	}
+}
+
+func TestParseTSVSingleColumn(t *testing.T) {
+	input := "count\n42\n"
+	headers, rows, err := ParseTSV(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(headers) != 1 || headers[0] != "count" {
+		t.Errorf("unexpected headers: %v", headers)
+	}
+	if len(rows) != 1 || rows[0][0] != "42" {
+		t.Errorf("unexpected rows: %v", rows)
+	}
+}
+
+func TestParseTSVHeaderOnly(t *testing.T) {
+	input := "name\tage\n"
+	headers, rows, err := ParseTSV(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(headers) != 2 {
+		t.Errorf("expected 2 headers, got %d", len(headers))
+	}
+	if len(rows) != 0 {
+		t.Errorf("expected 0 rows, got %d", len(rows))
+	}
+}
+
+func TestParseTSVEmpty(t *testing.T) {
+	_, _, err := ParseTSV("")
+	if err == nil {
+		t.Error("expected error for empty input")
+	}
+}
+
+func TestParseTSVTrailingNewlines(t *testing.T) {
+	input := "a\tb\n1\t2\n\n"
+	headers, rows, err := ParseTSV(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(headers) != 2 {
+		t.Errorf("expected 2 headers, got %d", len(headers))
+	}
+	if len(rows) != 1 {
+		t.Errorf("expected 1 row, got %d", len(rows))
+	}
+}

help.txt

@@ -9,6 +9,7 @@ Usage:
   showboat init <file> <title>             Create a new demo document
   showboat note <file> [text]              Append commentary (text or stdin)
   showboat exec <file> <lang> [code]       Run code and capture output
+  showboat exec <file> '<lang> {table}' [code]  Run code, render output as table
   showboat image <file> <path>             Copy image into document
   showboat image <file> '![alt](path)'   Copy image with alt text
   showboat pop <file>                      Remove the most recent entry
@@ -31,6 +32,25 @@ Exec output:
     $ echo $?
     1
 
+Table output:
+  When the language argument includes a {table} suffix, the exec command expects
+  the script to produce tab-separated (TSV) output. The first line is treated as
+  column headers and subsequent lines as data rows. The output is rendered as a
+  markdown pipe table instead of a plain output fence.
+
+  Any language works — the script just needs to print TSV to stdout:
+
+    $ showboat exec demo.md 'bash {table}' "printf 'name\tage\nAlice\t30\nBob\t25\n'"
+    name	age
+    Alice	30
+    Bob	25
+
+  Common patterns:
+    SQLite:   showboat exec d.md 'bash {table}' "sqlite3 -header -separator $'\t' db 'SELECT * FROM t'"
+    Postgres: showboat exec d.md 'bash {table}' "psql -A -F $'\t' -c 'SELECT * FROM t'"
+    Python:   showboat exec d.md 'python3 {table}' "import csv,sys; ..."
+    PySpark:  showboat exec d.md 'python3 {table}' "df.toPandas().to_csv(sys.stdout,sep='\t',index=False)"
+
 Image:
   The "image" command accepts a path to an image file or a markdown image
   reference of the form ![alt text](path). The image is copied into the same
@@ -82,6 +102,9 @@ Example:
   # Redo it correctly
   showboat exec demo.md python3 "print('Hello from Python')"
 
+  # Run a query and render the result as a table
+  showboat exec demo.md 'python3 {table}' "print('name\tage\nAlice\t30\nBob\t25')"
+
   # Add a screenshot
   showboat image demo.md screenshot.png
 
@@ -118,6 +141,15 @@ Resulting markdown format:
   Hello from Python
   ```
 
+  ```python3 {table}
+  print('name\tage\nAlice\t30\nBob\t25')
+  ```
+
+  | name | age |
+  | --- | --- |
+  | Alice | 30 |
+  | Bob | 25 |
+
   ```bash {image}
   screenshot.png
   ```

markdown/blocks.go

@@ -27,6 +27,7 @@ type CodeBlock struct {
 	Lang    string
 	Code    string
 	IsImage bool
+	IsTable bool
 }
 
 func (b CodeBlock) Type() string { return "code" }
@@ -45,3 +46,11 @@ type ImageOutputBlock struct {
 }
 
 func (b ImageOutputBlock) Type() string { return "output-image" }
+
+// TableOutputBlock is captured tabular output rendered as a markdown table.
+type TableOutputBlock struct {
+	Headers []string
+	Rows    [][]string
+}
+
+func (b TableOutputBlock) Type() string { return "output-table" }

markdown/blocks_test.go

@@ -36,3 +36,19 @@ func TestTitleBlock(t *testing.T) {
 		t.Errorf("expected type title, got %s", b.Type())
 	}
 }
+
+func TestTableOutputBlock(t *testing.T) {
+	b := TableOutputBlock{
+		Headers: []string{"name", "age"},
+		Rows:    [][]string{{"Alice", "30"}, {"Bob", "25"}},
+	}
+	if b.Type() != "output-table" {
+		t.Errorf("expected type output-table, got %s", b.Type())
+	}
+	if len(b.Headers) != 2 {
+		t.Errorf("expected 2 headers, got %d", len(b.Headers))
+	}
+	if len(b.Rows) != 2 {
+		t.Errorf("expected 2 rows, got %d", len(b.Rows))
+	}
+}