object

halstead_metric(Stroud)

  • Stroud - Coefficient for computing the time required to program.

Computes Halstead complexity numbers for an entity.

Author: Paulo Moura
Version: 0:7:0
Date: 2018-07-18
Compilation flags:
static, context_switching_calls
Imports:
public code_metrics_utilities
public code_metric
Uses:
list
numberlist
pairs
Remarks:

  • Definition of operators: Predicates declared, user-defined, and called are interpreted as operators. Built-in predicates and built-in control constructs are ignored.

  • Definition of operands: Predicate arguments are abstracted and interpreted as operands. Note that this definition of operands is a significant deviation from the original definition, which used syntactic literals.

  • Pn: Number of distinct predicates (declared, defined, called, or updated)

  • PAn: Number of predicate arguments (assumed distinct)

  • Cn: Number of predicate calls/updates + number of clauses

  • CAn: Number of predicate call/update arguments + number of clause head arguments

  • EV: Entity vocabulary: EV = Pn + PAn

  • EL: Entity length: EL = Cn + CAn

  • V: Volume: V = EL * log2(EV)

  • D: Difficulty: D = (Pn/2) * (CAn/An)

  • E: Effort: E = D * V

  • T: Time required to program: T = E/k seconds (k is the Stroud number; defaults to 18)

  • B: Number of delivered bugs: B = V/3000

  • Entity score: Represented as the compound term pn_pan_cn_can_ev_el_v_d_e_t_b/11.

Inherited public predicates:
 all/0  all_score/1  directory/1  directory_score/2  entity/1  entity_score/2  entity_score//2  file/1  file_score/2  library/1  library_score/2  rdirectory/1  rdirectory_score/2  rlibrary/1  rlibrary_score/2

Public predicates

(no local declarations; see entity ancestors if any)

Protected predicates

(no local declarations; see entity ancestors if any)

Private predicates

(no local declarations; see entity ancestors if any)

Operators

(none)