zuv-lang · rohitsoni007 · Aug 25, 2026 · Aug 25, 2026 · Aug 25, 2026 · Aug 25, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,6 +5,31 @@ All notable changes to the **Zuv** programming language and self-hosting compile
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+---
+
+## [0.6.0] - 2026-08-25
+
+### 🧱 Data Types
+- **Type Inspection Operator (`typ`)**: Added prefix `typ` operator returning type strings (`"str"`, `"num"`, `"bool"`, `"obj"`, `"arr"`, `"nil"`, `"und"`, `"sym"`, `"bigint"`). Implemented in C++ bootstrap and self-hosting compiler. `und` literal now distinct from `nil` for `typ und`. New test: `typ.test.zv`.
+- **Enums (`enum`)**: Named variants as integer discriminants (`0..n-1`). `Status.Active` property access, `mch` arms with qualified (`Status.Pending`) or bare (`Pending`) patterns. C++ bootstrap keeps native enum match; self-host desugars enum `mch` to nested `if`/`els`. Fixed self-host match-target parsing so `ident {` is not swallowed as a struct literal. New test: `enum.test.zv`.
+- **Undefined Literal (`und`)**: Runtime-distinct from `nil` (LLVM `bitcast i64 1 to double` sentinel). Equality/`!=`, falsy `if`/`wh`/`for`/`and`/`or`/`!` via truthiness helper, and `typ und` → `"und"`. Fixed C++ `TOK_UND` over-consume and self-host checker allowing `let x = nil|und`. New test: `und.test.zv`.
+- **Unique Symbol Primitive (`sym`)**: `sym "key"` creates an interned identity (same key → equal, different from strings). `typ (sym "k")` → `"sym"`. Symbols are truthy. Renamed self-host locals that collided with the new `sym` keyword. New test: `sym.test.zv`.
+- **BigInt Primitives (`BigInt` / `...n`)**: Digit-string bigint literals (`123n`) and `BigInt(...)` constructor. Equality via content (`strcmp`); distinct from numbers (`123n != 123`). `typ` → `"bigint"`. New test: `bigint.test.zv`.
+- **Scientific Exponent Literals (`123e5`, `1.5E-2`)**: Lexer support for `e`/`E` with optional `+`/`-` in C++ bootstrap and self-host. New test: `sci_notation.test.zv`.
+- **Number Bases (`0x` / `0b` / `0o`)**: Hex, binary, and octal integer literals in C++ bootstrap and self-host. New test: `bases.test.zv`.
+- **Special Numbers (`nan`, `inf` / `Infinity`)**: IEEE-754 NaN/+Inf literals; statement `inf expr` remains info logging. Helpers `isNan` / `isFin`. New test: `nan_inf.test.zv`.
+
+### ⚡ Operators
+- **Exponentiation (`**`)**: Right-associative `**` via `llvm.pow.f64`. New test: `pow.test.zv`.
+
+### 🔤 Self-Hosting Source Style
+- **Template Literals**: Migrated self-hosting compiler sources (`src/*.zv`) from `"..." + expr` concatenation and escaped `\"` strings to backtick templates with `${...}` interpolation (e.g. `` `tests/${impPath}.zv` ``). Plain string literals left unchanged.
+- **Shortform Methods**: Replaced long-form std method calls with shortforms used in the test suite — `.concat` → `.cat`, `.charAt` → `.chr`.
+
+---
+
 ## [0.5.0] - 2026-08-25
 
 ### 📦 Variables & Scope

diff --git a/src/checker.zv b/src/checker.zv
@@ -69,7 +69,7 @@ declareVar checker, name, isMut {
     existingInCurrent = findVarInCurrentScope checker, name
     if isMut == 1 {
         if existingInCurrent.name != "" {
-            errRedecl = "Variable '" + name + "' is already declared in this scope"
+            errRedecl = `Variable '${name}' is already declared in this scope`
             checker.errors.psh errRedecl
         } els {
             curIdx = checker.scopes.ln - 1
@@ -95,7 +95,7 @@ checkExpr checker, expr {
     if expr.kind == "VariableExpr" {
         v = findVarState checker, expr.name
         if v.name != "" && v.isMoved == 1 {
-            errVal = "Use of moved value: '" + expr.name + "'"
+            errVal = `Use of moved value: '${expr.name}'`
             checker.errors.psh errVal
         }
     } els if expr.kind == "UnaryExpr" {
@@ -105,22 +105,22 @@ checkExpr checker, expr {
                 v = findVarState checker, vName
                 if v.name != "" {
                     if v.isMoved == 1 {
-                        errMoved = "Cannot borrow moved value: '" + vName + "'"
+                        errMoved = `Cannot borrow moved value: '${vName}'`
                         checker.errors.psh errMoved
                     }
                     if expr.op == "&mut" {
                         if v.isMut == 0 {
-                            errImmut = "Cannot borrow immutable variable '" + vName + "' as mutable (&mut)"
+                            errImmut = `Cannot borrow immutable variable '${vName}' as mutable (&mut)`
                             checker.errors.psh errImmut
                         }
                         if v.immBorrows > 0 || v.mutBorrows > 0 {
-                            errActive = "Cannot borrow '" + vName + "' as mutable (&mut) because it is already borrowed"
+                            errActive = `Cannot borrow '${vName}' as mutable (&mut) because it is already borrowed`
                             checker.errors.psh errActive
                         }
                         v.mutBorrows = v.mutBorrows + 1
                     } els {
                         if v.mutBorrows > 0 {
-                            errMut = "Cannot borrow '" + vName + "' as immutable (&) because it is borrowed as mutable (&mut)"
+                            errMut = `Cannot borrow '${vName}' as immutable (&) because it is borrowed as mutable (&mut)`
                             checker.errors.psh errMut
                         }
                         v.immBorrows = v.immBorrows + 1
@@ -138,7 +138,7 @@ checkExpr checker, expr {
                 vName = expr.left.name
                 v = findVarState checker, vName
                 if v.name != "" && v.isMut == 0 {
-                    errMutate = "Cannot mutate immutable variable: '" + vName + "'"
+                    errMutate = `Cannot mutate immutable variable: '${vName}'`
                     checker.errors.psh errMutate
                 }
             }
@@ -169,8 +169,13 @@ checkExpr checker, expr {
 
 checkStatement checker, stmt {
     if stmt.kind == "VarDecl" {
-        if stmt.value.kind == "NilExpr" || stmt.value.kind == "" {
-            checker.errors.psh ("Semantic Error: Invalid variable initialization for '" + stmt.name + "'")
+        // Allow explicit nil/und literals; reject missing/placeholder inits
+        if stmt.value.kind == "" {
+            checker.errors.psh (`Semantic Error: Invalid variable initialization for '${stmt.name}'`)
+        } els if stmt.value.kind == "NilExpr" {
+            if stmt.value.val != "nil" && stmt.value.val != "und" {
+                checker.errors.psh (`Semantic Error: Invalid variable initialization for '${stmt.name}'`)
+            }
         }
         checkExpr checker, stmt.value
         declareVar checker, stmt.name, stmt.isMut
@@ -253,9 +258,9 @@ checkStatement checker, stmt {
     } els if stmt.kind == "ImportStmt" {
         let si = 0
         wh si < stmt.symbols.ln {
-            sym = stmt.symbols[si]
-            if sym != "" {
-                declareVar checker, sym, 0
+            impName = stmt.symbols[si]
+            if impName != "" {
+                declareVar checker, impName, 0
             }
             si = si + 1
         }

diff --git a/src/cli.zv b/src/cli.zv
@@ -29,7 +29,7 @@ emitDirectObjectFile ir, outputObjPath, isRelease {
     LLVMInitializeX86AsmPrinter
     LLVMInitializeX86AsmParser
 
-    fullIr = "target triple = \"x86_64-pc-windows-msvc\"\n" + ir
+    fullIr = `target triple = "x86_64-pc-windows-msvc"\n${ir}`
     ctx = LLVMGetGlobalContext
     memBuf = LLVMCreateMemoryBufferWithMemoryRange fullIr, fullIr.ln, "zuv_ir", 0
 
@@ -38,7 +38,7 @@ emitDirectObjectFile ir, outputObjPath, isRelease {
     res = LLVMParseIRInContext ctx, memBuf, outModPtr, outMsgPtr
     if res != 0 {
         errMsg = zuv_ptr_deref outMsgPtr
-        prnt ("[LLVM Error] IR Parse Failed: " + errMsg)
+        prnt (`[LLVM Error] IR Parse Failed: ${errMsg}`)
         -> 1
     }
     mod = zuv_ptr_deref outModPtr
@@ -48,7 +48,7 @@ emitDirectObjectFile ir, outputObjPath, isRelease {
     tRes = LLVMGetTargetFromTriple triple, targetPtr, outMsgPtr
     if tRes != 0 {
         errMsg2 = zuv_ptr_deref outMsgPtr
-        prnt ("[LLVM Error] Target lookup failed: " + errMsg2)
+        prnt (`[LLVM Error] Target lookup failed: ${errMsg2}`)
         LLVMDisposeModule mod
         -> 1
     }
@@ -63,7 +63,7 @@ emitDirectObjectFile ir, outputObjPath, isRelease {
     emitRes = LLVMTargetMachineEmitToFile tm, mod, outputObjPath, 1, outMsgPtr
     if emitRes != 0 {
         errMsg3 = zuv_ptr_deref outMsgPtr
-        prnt ("[LLVM Error] Object code emission failed: " + errMsg3)
+        prnt (`[LLVM Error] Object code emission failed: ${errMsg3}`)
         LLVMDisposeTargetMachine tm
         LLVMDisposeModule mod
         -> 1
@@ -81,7 +81,7 @@ linkDirectObjectFile objPath, outExePath {
     } els if fE "bin/lld-link.exe" {
         lldBin = "bin/lld-link.exe"
     }
-    cmd = lldBin + " \"" + objPath + "\" -out:\"" + outExePath + "\" -stack:33554432 -defaultlib:libcmt -defaultlib:legacy_stdio_definitions -defaultlib:oldnames -defaultlib:user32 -defaultlib:kernel32 -nologo"
+    cmd = `${lldBin} "${objPath}" -out:"${outExePath}" -stack:33554432 -defaultlib:libcmt -defaultlib:legacy_stdio_definitions -defaultlib:oldnames -defaultlib:user32 -defaultlib:kernel32 -nologo`
     res = system cmd
     -> res
 }
@@ -92,7 +92,7 @@ handleBuild targetFile, isRelease, emitLlvm, outExe {
         prnt "==========================================="
         prnt "     Zuv Self-Hosting Compiler [BUILD]     "
         prnt "==========================================="
-        prnt ("Compiling target file: " + targetFile)
+        prnt (`Compiling target file: ${targetFile}`)
 
         if isRelease == 1 {
             prnt "Optimization: Release Mode (-O3 Native)"
@@ -106,7 +106,7 @@ handleBuild targetFile, isRelease, emitLlvm, outExe {
         if prog.errors.ln > 0 {
             let pe = 0
             wh pe < prog.errors.ln {
-                prnt ("[zuv build] " + prog.errors[pe])
+                prnt (`[zuv build] ${prog.errors[pe]}`)
                 pe = pe + 1
             }
             -> 0
@@ -123,9 +123,9 @@ handleBuild targetFile, isRelease, emitLlvm, outExe {
                     impPath = s.paths[0]
                 }
                 if impPath != "" && impPath != "str" && impPath != "arr" && impPath != "fs" && impPath != "time" && impPath != "thread" && impPath != "thr" && impPath != "os" {
-                    let fullImpPath = impPath + ".zv"
+                    let fullImpPath = `${impPath}.zv`
                     if (fE fullImpPath) == 0 {
-                        fullImpPath = "tests/" + impPath + ".zv"
+                        fullImpPath = `tests/${impPath}.zv`
                     }
                     if (fE fullImpPath) == 1 {
                         impCode = rF fullImpPath
@@ -171,7 +171,7 @@ handleBuild targetFile, isRelease, emitLlvm, outExe {
                 prnt "[zuv build] Successfully generated output_selfhost.ll via self-hosting compiler!"
                 -> 1
             } els {
-                objPath = targetExe + ".obj"
+                objPath = `${targetExe}.obj`
                 emitRes = emitDirectObjectFile ir, objPath, isRelease
                 if emitRes != 0 {
                     prnt "[zuv build] Direct in-process LLVM object code generation failed."
@@ -183,9 +183,9 @@ handleBuild targetFile, isRelease, emitLlvm, outExe {
                 }
                 if linkRes == 0 {
                     if isRelease == 1 {
-                        prnt ("[zuv build] Successfully generated " + targetExe + " (-O3 Native In-Process)")
+                        prnt (`[zuv build] Successfully generated ${targetExe} (-O3 Native In-Process)`)
                     } els {
-                        prnt ("[zuv build] Successfully generated " + targetExe + " (Debug In-Process)")
+                        prnt (`[zuv build] Successfully generated ${targetExe} (Debug In-Process)`)
                     }
                     -> 1
                 } els {
@@ -198,7 +198,7 @@ handleBuild targetFile, isRelease, emitLlvm, outExe {
             -> 0
         }
     } els {
-        prnt ("[zuv build] Error: Could not open source file: " + targetFile)
+        prnt (`[zuv build] Error: Could not open source file: ${targetFile}`)
         -> 0
     }
 }
@@ -211,22 +211,22 @@ handleCheck targetFile {
         prog = parseProgramFull toks
         okSafety = checkProgram prog
         if okSafety == 1 {
-            prnt (" PASS " + targetFile)
+            prnt (` PASS ${targetFile}`)
             -> 1
         } els {
-            prnt (" FAIL " + targetFile + " (Semantic / Safety Check Failed)")
+            prnt (` FAIL ${targetFile} (Semantic / Safety Check Failed)`)
             -> 0
         }
     } els {
-        prnt (" FAIL " + targetFile + " (File Not Found)")
+        prnt (` FAIL ${targetFile} (File Not Found)`)
         -> 0
     }
 }
 
 handleRun targetFile {
     res = handleBuild targetFile, 0, 0, "output.exe"
     if res == 1 {
-        prnt ("[zuv run] Executing output.exe for " + targetFile)
+        prnt (`[zuv run] Executing output.exe for ${targetFile}`)
         sh ".\\output.exe"
     }
     -> res
@@ -235,10 +235,10 @@ handleRun targetFile {
 handleFmt targetFile {
     if fE targetFile {
         code = rF targetFile
-        prnt ("[zuv fmt] Formatted " + targetFile + " successfully.")
+        prnt (`[zuv fmt] Formatted ${targetFile} successfully.`)
         -> 1
     } els {
-        err ("[zuv fmt] Error: Could not open " + targetFile)
+        err (`[zuv fmt] Error: Could not open ${targetFile}`)
         -> 0
     }
 }
@@ -256,7 +256,7 @@ handleCheckAll {
     wh ti < tests.ln {
         tFile = tests[ti]
         if (tFile.cnt "error") > 0 {
-            prnt (" PASS " + tFile + " (Expected error caught)")
+            prnt (` PASS ${tFile} (Expected error caught)`)
             passCount = passCount + 1
         } els {
             r = handleCheck tFile
@@ -272,11 +272,11 @@ handleCheckAll {
     total = passCount + failCount
     prnt ""
     if failCount == 0 {
-        prnt (" Checked Files: " + passCount + " passed (" + total + ")")
-        prnt ("        Status: " + passCount + " passed")
+        prnt (` Checked Files: ${passCount} passed (${total})`)
+        prnt (`        Status: ${passCount} passed`)
     } els {
-        prnt (" Checked Files: " + failCount + " failed, " + passCount + " passed (" + total + ")")
-        prnt ("        Status: " + failCount + " failed, " + passCount + " passed")
+        prnt (` Checked Files: ${failCount} failed, ${passCount} passed (${total})`)
+        prnt (`        Status: ${failCount} failed, ${passCount} passed`)
     }
     prnt ""
     -> 1
@@ -307,26 +307,26 @@ handleTest {
         if isExpectedError == 1 {
             tElapsed = nw - tStart
             if buildOk == 0 {
-                prnt (" PASS " + tFile + " (" + tElapsed + "ms) [Expected Error]")
+                prnt (` PASS ${tFile} (${tElapsed}ms) [Expected Error]`)
                 passCount = passCount + 1
             } els {
-                prnt (" FAIL " + tFile + " (" + tElapsed + "ms) [Expected error but compiled]")
+                prnt (` FAIL ${tFile} (${tElapsed}ms) [Expected error but compiled]`)
                 failCount = failCount + 1
             }
         } els {
             if buildOk == 0 {
                 tElapsed = nw - tStart
-                prnt (" FAIL " + tFile + " (" + tElapsed + "ms) [Compilation Failed]")
+                prnt (` FAIL ${tFile} (${tElapsed}ms) [Compilation Failed]`)
                 failCount = failCount + 1
             } els {
-                runCmd = ".\\" + tempExe + " > nul 2>&1"
+                runCmd = `.\\${tempExe} > nul 2>&1`
                 runRes = sh runCmd
                 tElapsed = nw - tStart
                 if runRes == 0 {
-                    prnt (" PASS " + tFile + " (" + tElapsed + "ms)")
+                    prnt (` PASS ${tFile} (${tElapsed}ms)`)
                     passCount = passCount + 1
                 } els {
-                    prnt (" FAIL " + tFile + " (" + tElapsed + "ms) [Execution failed code " + runRes + "]")
+                    prnt (` FAIL ${tFile} (${tElapsed}ms) [Execution failed code ${runRes}]`)
                     failCount = failCount + 1
                 }
             }
@@ -342,13 +342,13 @@ handleTest {
     total = passCount + failCount
     prnt ""
     if failCount == 0 {
-        prnt (" Test Files: " + passCount + " passed (" + total + ")")
-        prnt ("      Tests: " + passCount + " passed")
+        prnt (` Test Files: ${passCount} passed (${total})`)
+        prnt (`      Tests: ${passCount} passed`)
     } els {
-        prnt (" Test Files: " + failCount + " failed, " + passCount + " passed (" + total + ")")
-        prnt ("      Tests: " + failCount + " failed, " + passCount + " passed")
+        prnt (` Test Files: ${failCount} failed, ${passCount} passed (${total})`)
+        prnt (`      Tests: ${failCount} failed, ${passCount} passed`)
     }
-    prnt ("   Duration: " + totalElapsed + "ms")
+    prnt (`   Duration: ${totalElapsed}ms`)
     prnt ""
     -> 1
 }