dissenting with whom EDMONDSON, V.C.J., KAUGER, WATT, JJ. join:
I 1 Today this Court refuses to apply time-honored rules of statutory construction and contract interpretation to avoid an absurd and illogical conclusion. It simply makes no sense to acknowledge the City's express obligation to provide a "post-disability retirement death" pension and then ignore the eligibility requirements reasonably implied by related provisions of the same document. I would enforce the City's unambiguous promise to provide a spouse's pension to this widow by applying well-established rules of construction to infer the eligibility requirements.
T2 The Employee Retirement System of Frederick, Oklahoma, was enacted as a municipal ordinance on September 27, 1966. As an ordinance, it is subject to the normal rules of statutory construction. Tinker Inv. & Mortgage Corp. v. City of Midwest City, 1994 OK 41, ¶ 13, 873 P.2d 1029, 1038. Because the System also forms a contract between the participating employees and the City, it is likewise subject to the normal rules of contract interpretation. Woods v. City of Lawton, 1992 OK 167, ¶ 7, 845 P.2d 880, 882; Bd. of Trs. v. Kern, 1961 OK 265, ¶ 7, 366 P.2d 415, 418. Appellant has the right to enforce its terms as a third-party beneficiary of the contract. Okla. Stat. tit. 15, § 29 (2001).
T3 The System creates five different types of pension: (1) an employee's pension following normal retirement, section 4.1; (2) an employee's pension following disability retirement, section 4.98; (8) a deferred vested employee's pension, section 44; (4) a spouse's pension, section 6.1; and (5) a survivor's pension, section 6.2. A spouse's pension, described in article VI, is not a continuation of any of the three kinds of employee's pension, described in article IV. In general, an employee's pension ends on the first day of the month of the employee's death. A spouse's pension does not commence until after the employee's death.
T4 Two cireumstances lead to a spouse's pension: (1) the "in-service death" of an active employee, described in section 6.1.B.1; and (2) the "post-disability retirement death" of a disabled employee, described in section 6.1.B.2. The System unambiguously expresses the City's intent to create a spouse's pension for the surviving spouse of a deceased retired employee who was receiving a disability pension:
8. Post-Disability Retirement Death: A surviving spouse who meets the eligibility requirements under Paragraph 2 of Subsection 6.1A shall receive a monthly amount of Spouse's Pension equal to the monthly amount of the Disability Pension which the retired Employee was receiving *76or was entitled to receive under this System on the date of his death.
The problem arises because there is no "Paragraph 2 of Subsection 6.1A" and, therefore, no eligibility requirements for a "post-disability retirement death" spouse's pension.
T5 This Court has an obligation to fill statutory omissions when the failure to do so would result in absurdity or thwart the purpose of the law. See Cox v. Dawson, 1996 OK 11, ¶ 6, 911 P.2d 272, 276; see also Fanning v. Brown, 2004 OK 7, ¶ 13, 85 P.3d 841, 846; Arrow Tool & Gauge v. Mead, 2000 OK 86, ¶ 15, 16 P.3d 1120, 1125-26; Maule v. Indep. Sch. Dist. No. 9, 1985 OK 110, ¶ 11, 714 P.2d 198, 203. ''It is a quintessential function of any court of last resort to interpret ambiguous statutes and thereby resolve actual justiciable controversies before it. By resolving this controversy we are not legislating. Rather, we are simply performing our constitutional duty.'' Cox, 1996 OK 11, ¶ 7 n. 11, 911 P.2d at 277 n. 11.
T6 This Court has accepted this responsibility in the past. In Cox, this Court drew on long-standing administrative rules, the Legislature's acquiescence in those rules, and the terms of similar statutes to supply essential but omitted details in a statute. Id. ¶¶ 22-24, 911 P.2d at 282. Similarly, in Arrow Tool, the Court "fashioned" a definition for "last order" based on practical considerations and the Legislature's intent. 2000 OK 86, ¶ 18, 16 P.3d at 1126. The Court reviewed the Nursing Home Care Act in For-?c 6 ning to conclude that a nursing home's "owner" included not only the entity holding legal title but also "person[s] or entitfies] halving] responsibility for providing the relevant services to residents." 2004 OK 7, ¶ 13, 85 P.3d at 846 (interpreting Okla. Stat. tit. 63, § 1-1901 through 1-1951 (2001)).
T7 Maule provides an excellent example of this Court's proper role of interpreting legislative enactments to reach a workable and coherent result. 1985 OK 110, ¶¶ 12-13, 714 P.2d at 203-04. In Maule, the Court weighed practical considerations to safeguard the Legislature's "overriding" intent and avoid a potentially unconstitutional application, even though it departed from the statute's express language to do so. Id. As Maule and the other cases demonstrate, this Court has not shirked its unique duty to interpret statutes to resolve actual controversies and further the law-making body's intent, even when the intended wording of missing or imprecise language is not readily apparent. Cox, 1996 OK 11, ¶ 7 n. 11, 911 P.2d at 277 n. 11.
T8 The task here, to determine the terms of omitted eligibility requirements, is not nearly so complicated. The Court is aided by the long-standing rule that ambiguous pension statutes must be interpreted in favor of the beneficiaries. In re Benson, 1936 OK 704, 10, 62 P.2d 962, 962 (syl. no. 3 by the Court). In addition, courts construe a contract most strongly against the party creating the ambiguity. Okla. Stat. tit 15, § 170 (2001). The City created the ambiguity here.1
T9 The City employed unambiguous language to create the spouse's pension: "A surviving spouse ... shall receive a monthly amount of Spouse's Pension equal to the monthly amount of the Disability Pension which the retired Employee was receiving." (Emphasis added.) The word "shall" is generally treated as mandatory-a nondiscre-tionary command-in both contracts and statutes. Osprey L.L.C. v. Kelly-Moore Paint Co., 1999 OK 50, ¶ 14 n. 12, 984 P.2d 194, 199 n. 12; U.S. v. Hobbs, 1996 OK 77, ¶ 7 n. 16, 921 P.2d 338, 342 n. 16. The City's inadvertent omission of the eligibility re*77quirements does not make the mandatory language disappear. "Whether the parties intentionally left out language.. or unwittingly neglected to [include] it, this Court is nonetheless constrained by the agreement {because wel cannot expand [a] contract to include obligations or rights which the parties themselves did not delineate." ENI Producing Props. Program L.P. v. Samson Inv. Co. 1999 OK 21, ¶¶ 11 & 17, 977 P.2d 1086, 1088-1089.
{10 Moreover, the terms of the missing paragraph are obvious under these circumstances. They can be based on the eligibility requirements for an "in-service death" spouse's pension in section 6.1.A.1: that, at the time of death, the employee has remained in active service lasting ten or more years and is not retired and that the employee and spouse are not legally separated. The "length-of-service" requirement is always met before the disability pension commences. The "not-retired" requirement is either irrelevant or is met indirectly when the employee is prevented from normal retirement by his or her disability. Only one requirement remains: lack of legal separation. Appellant has satisfied that requirement. - Neither the majority nor the City has proffered any other requirement that might be imposed, despite the uncertainty they both profess to find.
T 11 The Court errs when it offers the time limit on normal retirement pension benefits to support its refusal to determine the missing requirements. Article IV describes three types of employee's pension. Section 4.1 de-seribes a normal retirement pension, section 4.3 (there is no section 4.2) describes a disability retirement pension, and section 4.4 describes a deferred vested pension. Each independent section states the circumstances that will cause that form of pension to cease. Disability pensions and deferred vested pensions cease upon the employee's death. Only a normal retirement pension can continue beyond the employee's death, subject to a 60-month limit. Any benefits remaining after the normally retired employee's death within the 60-month limit would be paid to the employee's beneficiaries, not necessarily the surviving spouse. To the contrary, seetion 6.1.A.1 provides that a spouse's pension continues until the spouse's death or remarriage. There is no basis, therefore, for construing any spouse's pension using the time limit applied to a normal retirement pension.
{12 Even though no spouse's pension would ever be subject to the 60-month limit, the majority uses that limit to defend its refusal to consider the terms of the missing eligibility requirements for a spouse's pension. The majority's opinion first concludes, correctly, that the City's intent, unambiguously expressed in the System's text, is to treat the surviving spouse of a deceased employee on disability retirement like the surviving spouse of an active employee by granting each a spouse's pension. It then concludes, correctly, that the only ambiguity is created by the omission of the eligibility requirements. The Court strays when it asserts that it is "more reasonable" to treat the surviving spouse of a deceased employee on disability retirement like the surviving spouse of a deceased employee on normal retirement by applying the time limit on continued benefits paid to the beneficiaries of a normally retired employee. By going beyond the gap created by the missing language to question the City's underlying intent as unambiguously expressed in the System's text, the Court engages in the very "guesswork and conjecture" it claims it is trying to avoid. This argument "usurp[sl the legislative prerogative" in the truest sense.
1 13 When it is apparent that a legislative body has overlooked something when it enacted a law, this Court's proper role is to construe the law to achieve a workable result in light of the legislative body's intent. Maule, 1985 OK 110, ¶¶ 12-13, 714 P.2d at 203-04; see also Arrow Tool, 2000 OK 86, 15, 16 P.3d at 1125-26; Cox, 1996 OK 11, ¶ 7 n. 11, 911 P.2d at 277 n. 11. Similarly, interpreting the meaning of an ambiguous contract to give effect to the parties' intent is traditionally within this Court's purview. See, e.g., First Enter. Bank v. Be-Graphic, Inc., 2006 OK CIV APP 141, ¶ 15, 149 P.3d 1064, 1068. That solemn authority, whether it be exercised to construe a statute or interpret a contract, is not diminished when we *78must look beyond the express language (granting the pension in this instance) to the implied intent (eligibility requirements in this instance), so long as we can reasonably infer that intent.
1 14 Appellant is the surviving spouse of a man who died while receiving a disability pension from the City. The City executed a contract and enacted an ordinance that she shall receive a spouse's pension. The City's intent is unambiguous. The missing eligibility requirements can be reasonably inferred from related provisions. I would apply well-established precedent and direct the trial court to issue a judgment declaring that the Employee Retirement System of Frederick, Oklahoma, requires the City to pay a monthly spouse's pension to Appellant as the surviving, and not legally separated, spouse of a deceased retired employee who was receiving a disability pension at the time of his death.
. An ambiguous contract is interpreted most strongly against the party causing the ambiguity:
[The language of a contract should be interpreted most strongly against the party who caused the uncertainty to exist. The promisor is presumed to be such party, except in a contract between a public officer or body, as such, and a private party, in which it is presumed that all uncertainty was caused by the private party.
Okla. Stat. tit. 15, § 170 (2001). The evidentiary presumption that any ambiguity was created by the party drafting the contract can, therefore, be reversed when the contract is between a public body and a private party. Id.; State ex rel. West v. City of Sapulpa, 1916 OK 861, ¶ 0, 160 P. 489, 489 (syl. no. 3 by the Court). Here, it is undisputed that the City drafted the language and created the uncertainty.