better errors, and/or support

index.test.ts

@@ -451,7 +451,7 @@ test("file if",() => {
 })
 
 test("no endif should throw",() => {
-  expect(() => initRenderer("./testdata/no_end_if")).toThrow()
+  expect(() => initRenderer("./testdata/no_end_if")).toThrow("test.txt")
 })
 
 test("path vars cannot write outside target",() => {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@gregorlohaus/tdir",
-  "version": "0.1.9",
+  "version": "0.2.0",
   "license": "MIT",
   "type": "module",
   "main": "./dist/index.js",

parser.ts

@@ -1,5 +1,5 @@
 import { readdirSync, statSync, readFileSync } from "node:fs"
-import { join } from "node:path"
+import { join, relative } from "node:path"
 import { TextDecoder } from "node:util"
 import { getDirectiveTokens, splitArgs } from "./scanner"
 
@@ -36,10 +36,15 @@ function extractCondition(expr: string | undefined, vars: TemplateVariable[]) {
   throw new Error(`Invalid condition expression: ${expr}`)
 }
 
-function extractFromString(text: string, vars: TemplateVariable[]) {
+function extractFromString(text: string, vars: TemplateVariable[], source = "template") {
   for (const token of getDirectiveTokens(text)) {
     if (token.type === "if" || token.type === "elseif") {
+      try {
         extractCondition(token.condition, vars)
+      } catch (error) {
+        if (error instanceof Error) throw new Error(`${source}: ${error.message}`)
+        throw error
+      }
     }
   }
   for (const match of text.matchAll(VAR_RE)) {
@@ -47,7 +52,7 @@ function extractFromString(text: string, vars: TemplateVariable[]) {
   }
 }
 
-function validateIfBlocks(content: string, vars: TemplateVariable[]) {
+function validateIfBlocks(content: string, vars: TemplateVariable[], source: string) {
   const stack: { sawElse: boolean }[] = []
 
   for (const token of getDirectiveTokens(content)) {
@@ -59,22 +64,22 @@ function validateIfBlocks(content: string, vars: TemplateVariable[]) {
       stack.push({ sawElse: false })
     } else if (directive === "elseif") {
       const frame = stack[stack.length - 1]
-      if (!frame) throw new Error("Unexpected <@elseif> without <@if>")
-      if (frame.sawElse) throw new Error("Unexpected <@elseif> after <@else>")
+      if (!frame) throw new Error(`${source}: Unexpected <@elseif> without <@if>`)
+      if (frame.sawElse) throw new Error(`${source}: Unexpected <@elseif> after <@else>`)
       extractCondition(condition!, vars)
     } else if (directive === "else") {
       const frame = stack[stack.length - 1]
-      if (!frame) throw new Error("Unexpected <@else> without <@if>")
-      if (frame.sawElse) throw new Error("Unexpected duplicate <@else>")
+      if (!frame) throw new Error(`${source}: Unexpected <@else> without <@if>`)
+      if (frame.sawElse) throw new Error(`${source}: Unexpected duplicate <@else>`)
       frame.sawElse = true
     } else if (directive === "endif") {
-      if (stack.length === 0) throw new Error("Unexpected <@endif> without <@if>")
+      if (stack.length === 0) throw new Error(`${source}: Unexpected <@endif> without <@if>`)
       stack.pop()
     }
   }
 
   if (stack.length > 0) {
-    throw new Error("Unmatched <@if> without <@endif>")
+    throw new Error(`${source}: Unmatched <@if> without <@endif>`)
   }
 }
 
@@ -88,21 +93,22 @@ function isUtf8Text(buffer: Buffer): boolean {
   }
 }
 
-function walkDir(dirPath: string, vars: TemplateVariable[]) {
+function walkDir(dirPath: string, vars: TemplateVariable[], rootPath: string) {
   const entries = readdirSync(dirPath).sort()
   for (const entry of entries) {
     const fullPath = join(dirPath, entry)
-    extractFromString(entry, vars)
+    const relativePath = relative(rootPath, fullPath)
+    extractFromString(entry, vars, relativePath || entry)
 
     const stat = statSync(fullPath)
     if (stat.isDirectory()) {
-      walkDir(fullPath, vars)
+      walkDir(fullPath, vars, rootPath)
     } else if (stat.isFile()) {
       const content = readFileSync(fullPath)
       if (isUtf8Text(content)) {
         const text = content.toString("utf-8")
-        extractFromString(text, vars)
-        validateIfBlocks(text, vars)
+        extractFromString(text, vars, relativePath || fullPath)
+        validateIfBlocks(text, vars, relativePath || fullPath)
       }
     }
   }
@@ -110,7 +116,7 @@ function walkDir(dirPath: string, vars: TemplateVariable[]) {
 
 export function parse(dirPath: string): TemplateVariable[] {
   const vars: TemplateVariable[] = []
-  walkDir(dirPath, vars)
+  walkDir(dirPath, vars, dirPath)
   const seen = new Set<string>()
   return vars.filter(v => {
     const key = `${v.path}:${v.type}`