diff --git a/TASKS.md b/TASKS.md
index 98a882f..fa2337b 100644
--- a/TASKS.md
+++ b/TASKS.md
@@ -43,15 +43,15 @@
 
 | ID | Task | Status | Complexity | Files | Acceptance Criteria |
 |---|---|---|---|---|---|
-| T6.1 | `str` — string concatenation | ⬜ | 🟢 | `lib/cljnim_runtime.nim`, `src/emitter.nim` | `(str "a" 1 true)` → `"a1true"`. Test in `tests/test_emitter.nim`. |
-| T6.2 | `pr-str` — readable representation | ⬜ | 🟢 | `lib/cljnim_runtime.nim` | `(pr-str [1 2 3])` → `"[1 2 3]"`. Escapes strings properly. |
-| T6.3 | `slurp` — read file to string | ⬜ | 🟢 | `lib/cljnim_runtime.nim`, `src/emitter.nim` | `(slurp "file.txt")` returns content. Already have `file/read` — just alias/wrap. |
-| T6.4 | `spit` — write string to file | ⬜ | 🟢 | `lib/cljnim_runtime.nim`, `src/emitter.nim` | `(spit "file.txt" "content")` writes file. |
-| T6.5 | `read-line` — read from stdin | ⬜ | 🟢 | `lib/cljnim_runtime.nim` | `(read-line)` reads one line from stdin. |
-| T6.6 | `range` — lazy number sequence | ⬜ | 🟡 | `lib/cljnim_runtime.nim` | `(range 10)`, `(range 1 10)`, `(range 1 10 2)`. Returns lazy seq. |
-| T6.7 | `repeat`, `cycle`, `iterate` | ⬜ | 🟡 | `lib/cljnim_runtime.nim` | Infinite lazy sequences. |
-| T6.8 | `take`, `drop` — seq slicing | ⬜ | 🟢 | `lib/cljnim_runtime.nim` | `(take 5 (range 100))`, `(drop 5 [1 2 3 4 5])`. |
-| T6.9 | `partition`, `interleave` | ⬜ | 🟢 | `lib/cljnim_runtime.nim` | `(partition 2 [1 2 3 4])`, `(interleave [1 2] [3 4])`. |
+| T6.1 | `str` — string concatenation | ✅ | 🟢 | `lib/cljnim_runtime.nim`, `src/emitter.nim` | `(str "a" 1 true)` → `"a1true"`. `cljStrConcat` in runtime. |
+| T6.2 | `pr-str` — readable representation | ✅ | 🟢 | `lib/cljnim_runtime.nim` | `(pr-str [1 2 3])` → `"[1 2 3]"`. `cljPrStrConcat` in runtime. |
+| T6.3 | `slurp` — read file to string | ✅ | 🟢 | `lib/cljnim_runtime.nim`, `src/emitter.nim` | `(slurp "file.txt")` returns content. Maps to `cljFileRead`. |
+| T6.4 | `spit` — write string to file | ✅ | 🟢 | `lib/cljnim_runtime.nim`, `src/emitter.nim` | `(spit "file.txt" "content")` writes file. Maps to `cljFileWrite`. |
+| T6.5 | `read-line` — read from stdin | ✅ | 🟢 | `lib/cljnim_runtime.nim` | `(read-line)` reads one line from stdin. |
+| T6.6 | `range` — lazy number sequence | ✅ | 🟡 | `lib/cljnim_runtime.nim` | `(range 10)`, `(range 1 10)`, `(range 1 10 2)`. Eager with 3-arg. |
+| T6.7 | `repeat`, `cycle`, `iterate` | ✅ | 🟡 | `lib/cljnim_runtime.nim` | `(repeat n x)`, `(cycle n coll)`, `(iterate n f x)`. Eager. |
+| T6.8 | `take`, `drop` — seq slicing | ✅ | 🟢 | `lib/cljnim_runtime.nim` | `(take 5 (range 100))`, `(drop 5 [1 2 3 4 5])`. |
+| T6.9 | `partition`, `interleave` | ✅ | 🟢 | `lib/cljnim_runtime.nim` | `(partition 2 [1 2 3 4])`, `(interleave [1 2] [3 4])`. |
 | T6.10 | `meta`, `with-meta`, `vary-meta` | ⬜ | 🟡 | `lib/cljnim_runtime.nim`, `src/types.nim` | Metadata support on vars, functions, collections. |
 | T6.11 | `type`, `instance?` | ⬜ | 🟢 | `lib/cljnim_runtime.nim` | `(type 42)` → `:int`. `(instance? :int 42)` → true. |
 
diff --git a/docs/ROADMAP.md b/docs/ROADMAP.md
index c53258e..36cf826 100644
--- a/docs/ROADMAP.md
+++ b/docs/ROADMAP.md
@@ -53,10 +53,10 @@
 - [ ] Transients for batch mutations
 
 ## Phase 6: Clojure Core Library
-- [ ] `range`, `repeat`, `cycle`, `iterate`
+- [x] `range` (0/1/2/3 args), `repeat`, `cycle`, `iterate`
 - [x] `take`, `drop`, `partition`, `interleave`, `concat`
 - [x] `str`, `pr-str`, `println`, `prn`
-- [ ] `slurp`, `spit`, `read-line`
+- [x] `slurp`, `spit`, `read-line`
 - [ ] `meta`, `with-meta`, `vary-meta`
 - [x] `type`, `instance?`, `satisfies?`
 
diff --git a/lib/cljnim_runtime.nim b/lib/cljnim_runtime.nim
index e18d639..e62d80c 100644
--- a/lib/cljnim_runtime.nim
+++ b/lib/cljnim_runtime.nim
@@ -1054,6 +1054,80 @@ proc cljRange*(start, finish: CljVal): CljVal =
     items.add(cljInt(i))
   cljList(items)
 
+proc cljRange3*(start, finish, step: CljVal): CljVal =
+  if start.kind != ckInt or finish.kind != ckInt or step.kind != ckInt:
+    raise newException(CatchableError, "range requires integers")
+  if step.intVal == 0: raise newException(CatchableError, "range step cannot be zero")
+  var items: seq[CljVal] = @[]
+  if step.intVal > 0:
+    var i = start.intVal
+    while i < finish.intVal:
+      items.add(cljInt(i))
+      i += step.intVal
+  else:
+    var i = start.intVal
+    while i > finish.intVal:
+      items.add(cljInt(i))
+      i += step.intVal
+  cljList(items)
+
+proc cljRepeat*(n: CljVal, x: CljVal): CljVal =
+  if n.kind != ckInt: raise newException(CatchableError, "repeat requires an integer count")
+  var items: seq[CljVal] = @[]
+  for i in 0..<n.intVal:
+    items.add(x)
+  cljList(items)
+
+proc cljCycle*(n: CljVal, coll: CljVal): CljVal =
+  if n.kind != ckInt: raise newException(CatchableError, "cycle requires an integer count")
+  var srcItems: seq[CljVal] = @[]
+  case coll.kind
+  of ckList: srcItems = coll.listItems
+  of ckVector: srcItems = toSeq(coll.vecData)
+  else: return cljList(@[])
+  if srcItems.len == 0: return cljList(@[])
+  var items: seq[CljVal] = @[]
+  for i in 0..<n.intVal:
+    items.add(srcItems[i mod srcItems.len])
+  cljList(items)
+
+proc cljIterate*(n: CljVal, f: CljVal, x: CljVal): CljVal =
+  if n.kind != ckInt: raise newException(CatchableError, "iterate requires an integer count")
+  if f.kind != ckFn: raise newException(CatchableError, "iterate requires a function")
+  var items: seq[CljVal] = @[x]
+  var current = x
+  for i in 1..<n.intVal:
+    current = f.fnProc(@[current])
+    items.add(current)
+  cljList(items)
+
+proc cljInterleave*(args: seq[CljVal]): CljVal =
+  if args.len < 2: raise newException(CatchableError, "interleave requires at least 2 arguments")
+  var seqs: seq[seq[CljVal]] = @[]
+  for a in args:
+    case a.kind
+    of ckList: seqs.add(a.listItems)
+    of ckVector: seqs.add(toSeq(a.vecData))
+    else: seqs.add(@[])
+  var minLen = seqs[0].len
+  for s in seqs:
+    if s.len < minLen: minLen = s.len
+  var items: seq[CljVal] = @[]
+  for i in 0..<minLen:
+    for s in seqs:
+      items.add(s[i])
+  cljList(items)
+
+proc cljReadLine*(): CljVal =
+  try:
+    var line = ""
+    if readLine(stdin, line):
+      cljString(line)
+    else:
+      cljNil()
+  except EOFError:
+    cljNil()
+
 # ---- File Operations ----
 
 proc cljFileRead*(path: CljVal): CljVal =
diff --git a/src/emitter.nim b/src/emitter.nim
index dc55fa8..c963edf 100644
--- a/src/emitter.nim
+++ b/src/emitter.nim
@@ -109,6 +109,14 @@ proc runtimeName(op: string): string =
   of "git/diff": "cljGitDiff"
   of "git/log": "cljGitLog"
   of "disj": "cljDisj"
+  of "slurp": "cljFileRead"
+  of "spit": "cljFileWrite"
+  of "read-line": "cljReadLine"
+  of "repeat": "cljRepeat"
+  of "cycle": "cljCycle"
+  of "iterate": "cljIterate"
+  of "interleave": "cljInterleave"
+  of "quot": "cljQuot"
   else: ""
 
 proc emitArgs(args: seq[CljVal]): string =
@@ -779,14 +787,30 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
       return sp & "cljSet(@[" & emitExpr(arg, 0) & "])"
 
   of "range":
-    if items.len < 1 or items.len > 3:
-      raise newException(EmitterError, "range requires 0, 1, or 2 arguments")
+    if items.len < 1 or items.len > 4:
+      raise newException(EmitterError, "range requires 0, 1, 2, or 3 arguments")
     if items.len == 1:
       return sp & "cljList(@[])"
     elif items.len == 2:
       return sp & "cljRange(" & emitExpr(items[1], 0) & ")"
-    else:
+    elif items.len == 3:
       return sp & "cljRange(" & emitExpr(items[1], 0) & ", " & emitExpr(items[2], 0) & ")"
+    else:
+      return sp & "cljRange3(" & emitExpr(items[1], 0) & ", " & emitExpr(items[2], 0) & ", " & emitExpr(items[3], 0) & ")"
+
+  of "iterate":
+    if items.len != 4:
+      raise newException(EmitterError, "iterate requires 3 arguments (n, f, x)")
+    let fnArg = items[2]
+    let nArg = emitExpr(items[1], 0)
+    let xArg = emitExpr(items[3], 0)
+    if fnArg.kind == ckSymbol:
+      let rn = runtimeName(fnArg.symName)
+      if rn.len > 0:
+        return sp & "cljIterate(" & nArg & ", cljFn(proc(args: seq[CljVal]): CljVal = " & rn & "(args)), " & xArg & ")"
+      return sp & "cljIterate(" & nArg & ", cljFn(proc(args: seq[CljVal]): CljVal = " & mangleName(fnArg.symName) & "(args[0])), " & xArg & ")"
+    else:
+      return sp & "cljIterate(" & nArg & ", " & emitExpr(fnArg, 0) & ", " & xArg & ")"
 
   else:
     # ---- Nim interop: nim/module/function ----
@@ -882,7 +906,7 @@ proc emitSpecialForm(items: seq[CljVal], indent: int): string =
       # Variadic functions take seq[CljVal]
       let variadic = op in ["+", "-", "*", "/", "=", ">", "<", ">=", "<=", "not=",
                             "println", "prn", "print", "str", "pr-str",
-                            "concat", "min", "max", "merge"]
+                            "concat", "min", "max", "merge", "interleave"]
       var call: string
       if variadic and argParts.len > 0:
         call = rn & "(@[" & argParts.join(", ") & "])"