Pure Nim stack implementation based on sequences.
179 |Example:
180 |# Reverting a string using a stack 181 | 182 | import stacks 183 | 184 | let a = "Hello, World!" 185 | var s = Stack[char]() 186 | for letter in a: 187 | s.push(letter) 188 | 189 | var b: string 190 | while not s.isEmpty: 191 | b.add(s.pop) 192 | 193 | assert b == "!dlroW ,olleH"194 |
195 |
215 | Types
196 |-
197 |
198 |
EStackEmpty = object of CatchableError
199 | - 200 | 201 | 202 | 203 | 204 | 205 |
Stack[T] = object 206 | data: seq[T] 207 |
208 | - 209 | 210 | 211 | 212 | 213 | 214 |
216 |
330 |
331 | Procs
217 |-
218 |
219 |
proc newStack[T](capacity = 8): Stack[T]
220 | -
221 |
222 | Creates a new stack. Optionally, the initial capacity can be reserved via capacity parameter.
var a = newStack[int](capacity = 64)
223 | 224 |
225 |
226 | proc len[T](s: Stack[T]): int
227 | -
228 |
229 | Returns the number of elements in the stack. Returns 0 if the stack is empty.
var a = newStack[int]() 230 | assert a.len == 0 231 | a.push(10); a.push(20) 232 | assert a.len == 2
233 | 234 |
235 |
236 | proc empty[T](s: Stack[T]): bool {...}{.deprecated: "use isEmpty() instead".}
237 | - 238 | 241 | 242 | 243 | 244 | 245 | 246 |
proc isEmpty[T](s: Stack[T]): bool
247 | -
248 |
249 | Returns true if stack contains no elements, false otherwise.
var a = newStack[int]() 250 | assert a.isEmpty == true 251 | a.push(10) 252 | assert a.isEmpty == false
253 | 254 |
255 |
256 | proc push[T](s: var Stack[T]; element: T)
257 | -
258 |
259 | Pushes element onto the top of the stack.
var a = newStack[int]() 260 | a.push(10)
261 | 262 |
263 |
264 | proc pop[T](s: var Stack[T]): T {...}{.raises: [EStackEmpty].}
265 | -
266 |
267 | Pops the top element from the stack. Raises EStackEmpty exception if the stack is empty.
var a = newStack[int]() 268 | a.push(10) 269 | discard a.pop() 270 | doAssertRaises(EStackEmpty, echo a.pop())
271 | 272 |
273 |
274 | proc popUnsafe[T](s: var Stack[T]): T
275 | -
276 |
277 | Pops the top element from the stack without checking if it's not empty. Make sure the stack is not empty.
var a = newStack[int]() 278 | a.push(10) 279 | check(a.popUnsafe() == 10)
280 | 281 |
282 |
283 | proc peek[T](s: Stack[T]): T {...}{.raises: [EStackEmpty].}
284 | -
285 |
286 | Peeks the top element from the stack. Raises EStackEmpty exception if the stack is empty.
var a = newStack[int]() 287 | a.push(10) 288 | check(a.peek() == 10)
289 | 290 |
291 |
292 | proc peekUnsafe[T](s: Stack[T]): T
293 | -
294 |
295 | Peeks the top element from the stack without checking if it's not empty. Make sure the stack is not empty.
var a = newStack[int]() 296 | a.push(10) 297 | check(a.peekUnsafe() == 10)
298 | 299 |
300 |
301 | proc clear[T](s: var Stack[T])
302 | -
303 |
304 | Empties the stack. Does nothing if the stack is already empty.
var a = newStack[int]() 305 | a.push(10) 306 | a.clear() 307 | assert a.isEmpty == true
308 | 309 |
310 |
311 | proc toSeq[T](s: Stack[T]): seq[T]
312 | -
313 |
314 | Returns sequence representation of a stack.
var a = newStack[int]() 315 | a.push(10); a.push(20) 316 | assert a.toSeq() == @[10, 20]
317 | 318 |
319 |
320 | proc `$`[T](s: Stack[T]): string
321 | -
322 |
323 | Returns string representation of a stack
var a = newStack[int]() 324 | a.push(10); a.push(20) 325 | assert $a == "Stack[10, 20]"
326 | 327 |
328 |
329 |