Release 5

This page is part of the FHIR Specification (v5.0.0: R5 - STU). This is the current published version. For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4

Example StructureDefinition/Expression (JSON)

Modeling and Methodology Work GroupMaturity Level: N/AStandards Status: Informative

Raw JSON (canonical form + also see JSON Format Specification)

StructureDefinition for Expression

{
  "resourceType" : "StructureDefinition",
  "id" : "Expression",
  "text" : {
    "status" : "generated",
    "div" : "<div xmlns=\"http://www.w3.org/1999/xhtml\"><table border=\"0\" cellpadding=\"0\" cellspacing=\"0\" style=\"border: 0px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align: top;\"><tr style=\"border: 1px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align: top\"><th style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views\" title=\"The logical name of the element\">Name</a></th><th style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views\" title=\"Information about the use of the element\">Flags</a></th><th style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views\" title=\"Minimum and Maximum # of times the the element can appear in the instance\">Card.</a></th><th style=\"width: 100px\" class=\"hierarchy\"><a href=\"https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views\" title=\"Reference to the type of the element\">Type</a></th><th style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views\" title=\"Additional information about the element\">Description &amp; Constraints</a><span style=\"float: right\"><a href=\"https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views\" title=\"Legend for this format\"><img src=\"data:image/png;base64,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\" alt=\"doco\" style=\"background-color: inherit\"/></a></span></th></tr><tr style=\"border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white\"><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAJUlEQVR4Xu3IIQEAAAgDsHd9/w4EQIOamFnaBgAA4MMKAACAKwNp30CqZFfFmwAAAABJRU5ErkJggg==)\" class=\"hierarchy\"><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,R0lGODlhEAAQAPQfAOvGUf7ztuvPMf/78/fkl/Pbg+u8Rvjqteu2Pf3zxPz36Pz0z+vTmPzurPvuw/npofbjquvNefHVduuyN+uuMu3Oafbgjfnqvf/3zv/3xevPi+vRjP/20/bmsP///wD/ACH5BAEKAB8ALAAAAAAQABAAAAVl4CeOZGme5qCqqDg8jyVJaz1876DsmAQAgqDgltspMEhMJoMZ4iy6I1AooFCIv+wKybziALVAoAEjYLwDgGIpJhMslgxaLR4/3rMAWoBp32V5exg8Shl1ckRUQVaMVkQ2kCstKCEAOw==\" alt=\".\" style=\"background-color: white; background-color: inherit\" title=\"Element\" class=\"hierarchy\"/> <a href=\"metadatatypes-definitions.html#Expression\" title=\"Expression : A expression that is evaluated in a specified context and returns a value. The context of use of the expression must specify the context in which the expression is evaluated, and how the result of the expression is used.\">Expression</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a style=\"padding-left: 3px; padding-right: 3px; color: black; null\" href=\"elementdefinition-definitions.html#ElementDefinition.isSummary\" title=\"This element is included in summaries\">Σ</a><a style=\"padding-left: 3px; padding-right: 3px; border: 1px grey solid; font-weight: bold; color: black; background-color: #fff5e6\" href=\"versions.html#std-process\" title=\"Standards Status = Trial Use\">TU</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"types.html#Element\">Element</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">An expression that can be used to generate a value<br/><span style=\"font-style: italic\" title=\"exp-1\">+ Rule: An expression or a reference must be provided</span><br/><span style=\"font-style: italic\" title=\"exp-2\">+ Rule: The name must be a valid variable name in most computer languages</span><br/><br/>Elements defined in Ancestors: <a href=\"types.html#Element\" title=\"Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.\">id</a>, <a href=\"types.html#Element\" title=\"May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.\">extension</a></td></tr>\r\n<tr style=\"border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7\"><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAALUlEQVR4Xu3IoREAIAwEwfT6/ddA0GBAxO3NrLlKUj9263wAAAAvrgEAADClAVWFQIBRHMicAAAAAElFTkSuQmCC)\" class=\"hierarchy\"><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAACXBIWXMAAAsTAAALEwEAmpwYAAAARklEQVQ4y2P8//8/AyWAhYFCMAgMuHjx4n+KXaCv+I0szW8WpCG8kFO1lGFKW/SIjAUYgxz/MzAwMDC+nqhDUTQyjuYFBgCNmhP4OvTRgwAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: #F7F7F7; background-color: inherit\" title=\"Primitive Data Type\" class=\"hierarchy\"/> <a href=\"metadatatypes-definitions.html#Expression.description\" title=\"Expression.description : A brief, natural language description of the condition that effectively communicates the intended semantics.\">description</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a style=\"padding-left: 3px; padding-right: 3px; color: black; null\" href=\"elementdefinition-definitions.html#ElementDefinition.isSummary\" title=\"This element is included in summaries\">Σ</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">0..1</td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"datatypes.html#string\">string</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">Natural language description of the condition<br/></td></tr>\r\n<tr style=\"border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white\"><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAALUlEQVR4Xu3IoREAIAwEwfT6/ddA0GBAxO3NrLlKUj9263wAAAAvrgEAADClAVWFQIBRHMicAAAAAElFTkSuQmCC)\" class=\"hierarchy\"><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAACXBIWXMAAAsTAAALEwEAmpwYAAAARklEQVQ4y2P8//8/AyWAhYFCMAgMuHjx4n+KXaCv+I0szW8WpCG8kFO1lGFKW/SIjAUYgxz/MzAwMDC+nqhDUTQyjuYFBgCNmhP4OvTRgwAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: white; background-color: inherit\" title=\"Primitive Data Type\" class=\"hierarchy\"/> <a href=\"metadatatypes-definitions.html#Expression.name\" title=\"Expression.name : A short name assigned to the expression to allow for multiple reuse of the expression in the context where it is defined.\">name</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a style=\"padding-left: 3px; padding-right: 3px; color: black; null\" href=\"elementdefinition-definitions.html#ElementDefinition.isSummary\" title=\"This element is included in summaries\">Σ</a><a style=\"padding-left: 3px; padding-right: 3px; border: 1px maroon solid; font-weight: bold; color: #301212; background-color: #fdf4f4;\" href=\"conformance-rules.html#constraints\" title=\"This element has or is affected by some invariants\">C</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">0..1</td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"datatypes.html#code\">code</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">Short name assigned to expression for reuse<br/></td></tr>\r\n<tr style=\"border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7\"><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAALUlEQVR4Xu3IoREAIAwEwfT6/ddA0GBAxO3NrLlKUj9263wAAAAvrgEAADClAVWFQIBRHMicAAAAAElFTkSuQmCC)\" class=\"hierarchy\"><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAACXBIWXMAAAsTAAALEwEAmpwYAAAARklEQVQ4y2P8//8/AyWAhYFCMAgMuHjx4n+KXaCv+I0szW8WpCG8kFO1lGFKW/SIjAUYgxz/MzAwMDC+nqhDUTQyjuYFBgCNmhP4OvTRgwAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: #F7F7F7; background-color: inherit\" title=\"Primitive Data Type\" class=\"hierarchy\"/> <a href=\"metadatatypes-definitions.html#Expression.language\" title=\"Expression.language : The media type of the language for the expression.\">language</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a style=\"padding-left: 3px; padding-right: 3px; color: black; null\" href=\"elementdefinition-definitions.html#ElementDefinition.isSummary\" title=\"This element is included in summaries\">Σ</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">0..1</td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"datatypes.html#code\">code</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">text/cql | text/fhirpath | application/x-fhir-query | etc.<br/>Binding: <a href=\"valueset-expression-language.html\" title=\"The media type of the expression language.\">Expression Language</a> (<a href=\"terminologies.html#extensible\" title=\"To be conformant, the concept in this element SHALL be from the specified value set if any of the codes within the value set can apply to the concept being communicated.  If the value set does not cover the concept (based on human review), alternate codings (or, data type allowing, text) may be included instead.\">Extensible</a>)<table class=\"grid\"><tr><td style=\"font-size: 11px\"><b>Additional Bindings</b></td><td style=\"font-size: 11px\">Purpose</td></tr><tr><td style=\"font-size: 11px\"><a href=\"valueset-mimetypes.html\" title=\"http://hl7.org/fhir/ValueSet/mimetypes\">Mime Types</a></td><td style=\"font-size: 11px\"><a href=\"valueset-additional-binding-purpose.html#additional-binding-purpose-maximum\" title=\"A required binding, for use when the binding strength is 'extensible' or 'preferred'\">Max Binding</a></td></tr></table><br/></td></tr>\r\n<tr style=\"border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white\"><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAALUlEQVR4Xu3IoREAIAwEwfT6/ddA0GBAxO3NrLlKUj9263wAAAAvrgEAADClAVWFQIBRHMicAAAAAElFTkSuQmCC)\" class=\"hierarchy\"><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAACXBIWXMAAAsTAAALEwEAmpwYAAAARklEQVQ4y2P8//8/AyWAhYFCMAgMuHjx4n+KXaCv+I0szW8WpCG8kFO1lGFKW/SIjAUYgxz/MzAwMDC+nqhDUTQyjuYFBgCNmhP4OvTRgwAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: white; background-color: inherit\" title=\"Primitive Data Type\" class=\"hierarchy\"/> <a href=\"metadatatypes-definitions.html#Expression.expression\" title=\"Expression.expression : An expression in the specified language that returns a value.\">expression</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a style=\"padding-left: 3px; padding-right: 3px; color: black; null\" href=\"elementdefinition-definitions.html#ElementDefinition.isSummary\" title=\"This element is included in summaries\">Σ</a><a style=\"padding-left: 3px; padding-right: 3px; border: 1px maroon solid; font-weight: bold; color: #301212; background-color: #fdf4f4;\" href=\"conformance-rules.html#constraints\" title=\"This element has or is affected by some invariants\">C</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">0..1</td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"datatypes.html#string\">string</a></td><td style=\"vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">Expression in specified language<br/></td></tr>\r\n<tr style=\"border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7\"><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAJUlEQVR4Xu3IIQEAAAgDsHd9/w4EQIOamFnaBgAA4MMKAACAKwNp30CqZFfFmwAAAABJRU5ErkJggg==)\" class=\"hierarchy\"><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzME+lXFigAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+3OsRUAIAjEUOL+O8cJABttJM11/x1qZAGqRBEVcNIqdWj1efDqQbb3HwwwwEfABmQUHSPM9dtDAAAAAElFTkSuQmCC\" alt=\".\" style=\"background-color: inherit\" class=\"hierarchy\"/><img src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAACXBIWXMAAAsTAAALEwEAmpwYAAAARklEQVQ4y2P8//8/AyWAhYFCMAgMuHjx4n+KXaCv+I0szW8WpCG8kFO1lGFKW/SIjAUYgxz/MzAwMDC+nqhDUTQyjuYFBgCNmhP4OvTRgwAAAABJRU5ErkJggg==\" alt=\".\" style=\"background-color: #F7F7F7; background-color: inherit\" title=\"Primitive Data Type\" class=\"hierarchy\"/> <a href=\"metadatatypes-definitions.html#Expression.reference\" title=\"Expression.reference : A URI that defines where the expression is found.\">reference</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a style=\"padding-left: 3px; padding-right: 3px; color: black; null\" href=\"elementdefinition-definitions.html#ElementDefinition.isSummary\" title=\"This element is included in summaries\">Σ</a><a style=\"padding-left: 3px; padding-right: 3px; border: 1px maroon solid; font-weight: bold; color: #301212; background-color: #fdf4f4;\" href=\"conformance-rules.html#constraints\" title=\"This element has or is affected by some invariants\">C</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">0..1</td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\"><a href=\"datatypes.html#uri\">uri</a></td><td style=\"vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px\" class=\"hierarchy\">Where the expression is found<br/></td></tr>\r\n<tr><td colspan=\"5\" class=\"hierarchy\"><br/><a href=\"https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views\" title=\"Legend for this format\"><img src=\"data:image/png;base64,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\" alt=\"doco\" style=\"background-color: inherit\"/> Documentation for this format</a></td></tr></table></div>"
  },
  "extension" : [{
    "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
    "valueCode" : "trial-use"
  }],
  "url" : "http://hl7.org/fhir/StructureDefinition/Expression",
  "version" : "5.0.0",
  "name" : "Expression",
  "status" : "draft",
  "experimental" : false,
  "date" : "2023-03-26T15:21:02+11:00",
  "publisher" : "HL7 FHIR Standard",
  "contact" : [{
    "telecom" : [{
      "system" : "url",
      "value" : "http://hl7.org/fhir"
    }]
  }],
  "description" : "Expression Type: A expression that is evaluated in a specified context and returns a value. The context of use of the expression must specify the context in which the expression is evaluated, and how the result of the expression is used.",
  "jurisdiction" : [{
    "coding" : [{
      "system" : "http://unstats.un.org/unsd/methods/m49/m49.htm",
      "code" : "001",
      "display" : "World"
    }]
  }],
  "fhirVersion" : "5.0.0",
  "mapping" : [{
    "identity" : "rim",
    "uri" : "http://hl7.org/v3",
    "name" : "RIM Mapping"
  }],
  "kind" : "complex-type",
  "abstract" : false,
  "type" : "Expression",
  "baseDefinition" : "http://hl7.org/fhir/StructureDefinition/DataType",
  "derivation" : "specialization",
  "snapshot" : {
    "element" : [{
      "id" : "Expression",
      "extension" : [{
        "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
        "valueCode" : "trial-use"
      }],
      "path" : "Expression",
      "short" : "An expression that can be used to generate a value",
      "definition" : "A expression that is evaluated in a specified context and returns a value. The context of use of the expression must specify the context in which the expression is evaluated, and how the result of the expression is used.",
      "min" : 0,
      "max" : "*",
      "base" : {
        "path" : "Expression",
        "min" : 0,
        "max" : "*"
      },
      "constraint" : [{
        "key" : "ele-1",
        "severity" : "error",
        "human" : "All FHIR elements must have a @value or children",
        "expression" : "hasValue() or (children().count() > id.count())",
        "source" : "http://hl7.org/fhir/StructureDefinition/Element"
      },
      {
        "key" : "exp-1",
        "severity" : "error",
        "human" : "An expression or a reference must be provided",
        "expression" : "expression.exists() or reference.exists()",
        "source" : "http://hl7.org/fhir/StructureDefinition/Expression"
      },
      {
        "key" : "exp-2",
        "severity" : "error",
        "human" : "The name must be a valid variable name in most computer languages",
        "expression" : "name.hasValue() implies name.matches('[A-Za-z][A-Za-z0-9\\\\_]{0,63}')",
        "source" : "http://hl7.org/fhir/StructureDefinition/Expression"
      }],
      "isModifier" : false,
      "mapping" : [{
        "identity" : "rim",
        "map" : "n/a"
      }]
    },
    {
      "id" : "Expression.id",
      "path" : "Expression.id",
      "representation" : ["xmlAttr"],
      "short" : "Unique id for inter-element referencing",
      "definition" : "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "Element.id",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "extension" : [{
          "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type",
          "valueUrl" : "id"
        }],
        "code" : "http://hl7.org/fhirpath/System.String"
      }],
      "condition" : ["ele-1"],
      "isModifier" : false,
      "isSummary" : false,
      "mapping" : [{
        "identity" : "rim",
        "map" : "n/a"
      }]
    },
    {
      "id" : "Expression.extension",
      "path" : "Expression.extension",
      "slicing" : {
        "discriminator" : [{
          "type" : "value",
          "path" : "url"
        }],
        "description" : "Extensions are always sliced by (at least) url",
        "rules" : "open"
      },
      "short" : "Additional content defined by implementations",
      "definition" : "May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.",
      "comment" : "There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.",
      "alias" : ["extensions",
      "user content"],
      "min" : 0,
      "max" : "*",
      "base" : {
        "path" : "Element.extension",
        "min" : 0,
        "max" : "*"
      },
      "type" : [{
        "code" : "Extension"
      }],
      "constraint" : [{
        "key" : "ele-1",
        "severity" : "error",
        "human" : "All FHIR elements must have a @value or children",
        "expression" : "hasValue() or (children().count() > id.count())",
        "source" : "http://hl7.org/fhir/StructureDefinition/Element"
      },
      {
        "key" : "ext-1",
        "severity" : "error",
        "human" : "Must have either extensions or value[x], not both",
        "expression" : "extension.exists() != value.exists()",
        "source" : "http://hl7.org/fhir/StructureDefinition/Extension"
      }],
      "isModifier" : false,
      "isSummary" : false,
      "mapping" : [{
        "identity" : "rim",
        "map" : "n/a"
      }]
    },
    {
      "id" : "Expression.description",
      "path" : "Expression.description",
      "short" : "Natural language description of the condition",
      "definition" : "A brief, natural language description of the condition that effectively communicates the intended semantics.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "Expression.description",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      }],
      "constraint" : [{
        "key" : "ele-1",
        "severity" : "error",
        "human" : "All FHIR elements must have a @value or children",
        "expression" : "hasValue() or (children().count() > id.count())",
        "source" : "http://hl7.org/fhir/StructureDefinition/Element"
      }],
      "isModifier" : false,
      "isSummary" : true
    },
    {
      "id" : "Expression.name",
      "extension" : [{
        "url" : "http://hl7.org/fhir/tools/StructureDefinition/no-binding",
        "valueBoolean" : true
      }],
      "path" : "Expression.name",
      "short" : "Short name assigned to expression for reuse",
      "definition" : "A short name assigned to the expression to allow for multiple reuse of the expression in the context where it is defined.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "Expression.name",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "code"
      }],
      "condition" : ["exp-2"],
      "constraint" : [{
        "key" : "ele-1",
        "severity" : "error",
        "human" : "All FHIR elements must have a @value or children",
        "expression" : "hasValue() or (children().count() > id.count())",
        "source" : "http://hl7.org/fhir/StructureDefinition/Element"
      }],
      "isModifier" : false,
      "isSummary" : true
    },
    {
      "id" : "Expression.language",
      "path" : "Expression.language",
      "short" : "text/cql | text/fhirpath | application/x-fhir-query | etc.",
      "definition" : "The media type of the language for the expression.",
      "requirements" : "The cardinality of this element is optional to allow text only as part of the authoring process.  However, in order to be executable, the expression element must be specified.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "Expression.language",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "code"
      }],
      "constraint" : [{
        "key" : "ele-1",
        "severity" : "error",
        "human" : "All FHIR elements must have a @value or children",
        "expression" : "hasValue() or (children().count() > id.count())",
        "source" : "http://hl7.org/fhir/StructureDefinition/Element"
      }],
      "isModifier" : false,
      "isSummary" : true,
      "binding" : {
        "extension" : [{
          "url" : "http://hl7.org/fhir/tools/StructureDefinition/binding-definition",
          "valueString" : "The media type of the expression language."
        },
        {
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName",
          "valueString" : "ExpressionLanguage"
        }],
        "strength" : "extensible",
        "description" : "The media type of the expression language.",
        "valueSet" : "http://hl7.org/fhir/ValueSet/expression-language",
        "additional" : [{
          "purpose" : "maximum",
          "valueSet" : "http://hl7.org/fhir/ValueSet/mimetypes"
        }]
      }
    },
    {
      "id" : "Expression.expression",
      "path" : "Expression.expression",
      "short" : "Expression in specified language",
      "definition" : "An expression in the specified language that returns a value.",
      "comment" : "If Expression.expression and Expression.reference are both present, the Expression.expression might just be a name pointing something within the referenced content.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "Expression.expression",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "string"
      }],
      "condition" : ["exp-1"],
      "constraint" : [{
        "key" : "ele-1",
        "severity" : "error",
        "human" : "All FHIR elements must have a @value or children",
        "expression" : "hasValue() or (children().count() > id.count())",
        "source" : "http://hl7.org/fhir/StructureDefinition/Element"
      }],
      "isModifier" : false,
      "isSummary" : true
    },
    {
      "id" : "Expression.reference",
      "path" : "Expression.reference",
      "short" : "Where the expression is found",
      "definition" : "A URI that defines where the expression is found.",
      "comment" : "If both a reference and an expression is found, the reference SHALL point to the same expression.",
      "min" : 0,
      "max" : "1",
      "base" : {
        "path" : "Expression.reference",
        "min" : 0,
        "max" : "1"
      },
      "type" : [{
        "code" : "uri"
      }],
      "condition" : ["exp-1"],
      "constraint" : [{
        "key" : "ele-1",
        "severity" : "error",
        "human" : "All FHIR elements must have a @value or children",
        "expression" : "hasValue() or (children().count() > id.count())",
        "source" : "http://hl7.org/fhir/StructureDefinition/Element"
      }],
      "isModifier" : false,
      "isSummary" : true
    }]
  },
  "differential" : {
    "element" : [{
      "id" : "Expression",
      "extension" : [{
        "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status",
        "valueCode" : "trial-use"
      }],
      "path" : "Expression",
      "short" : "An expression that can be used to generate a value",
      "definition" : "A expression that is evaluated in a specified context and returns a value. The context of use of the expression must specify the context in which the expression is evaluated, and how the result of the expression is used.",
      "min" : 0,
      "max" : "*",
      "constraint" : [{
        "key" : "exp-2",
        "severity" : "error",
        "human" : "The name must be a valid variable name in most computer languages",
        "expression" : "name.hasValue() implies name.matches('[A-Za-z][A-Za-z0-9\\\\_]{0,63}')",
        "source" : "http://hl7.org/fhir/StructureDefinition/Expression"
      },
      {
        "key" : "exp-1",
        "severity" : "error",
        "human" : "An expression or a reference must be provided",
        "expression" : "expression.exists() or reference.exists()",
        "source" : "http://hl7.org/fhir/StructureDefinition/Expression"
      }]
    },
    {
      "id" : "Expression.description",
      "path" : "Expression.description",
      "short" : "Natural language description of the condition",
      "definition" : "A brief, natural language description of the condition that effectively communicates the intended semantics.",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "string"
      }],
      "isSummary" : true
    },
    {
      "id" : "Expression.name",
      "extension" : [{
        "url" : "http://hl7.org/fhir/tools/StructureDefinition/no-binding",
        "valueBoolean" : true
      }],
      "path" : "Expression.name",
      "short" : "Short name assigned to expression for reuse",
      "definition" : "A short name assigned to the expression to allow for multiple reuse of the expression in the context where it is defined.",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "code"
      }],
      "condition" : ["exp-2"],
      "isSummary" : true
    },
    {
      "id" : "Expression.language",
      "path" : "Expression.language",
      "short" : "text/cql | text/fhirpath | application/x-fhir-query | etc.",
      "definition" : "The media type of the language for the expression.",
      "requirements" : "The cardinality of this element is optional to allow text only as part of the authoring process.  However, in order to be executable, the expression element must be specified.",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "code"
      }],
      "isSummary" : true,
      "binding" : {
        "extension" : [{
          "url" : "http://hl7.org/fhir/tools/StructureDefinition/binding-definition",
          "valueString" : "The media type of the expression language."
        },
        {
          "url" : "http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName",
          "valueString" : "ExpressionLanguage"
        }],
        "strength" : "extensible",
        "description" : "The media type of the expression language.",
        "valueSet" : "http://hl7.org/fhir/ValueSet/expression-language",
        "additional" : [{
          "purpose" : "maximum",
          "valueSet" : "http://hl7.org/fhir/ValueSet/mimetypes"
        }]
      }
    },
    {
      "id" : "Expression.expression",
      "path" : "Expression.expression",
      "short" : "Expression in specified language",
      "definition" : "An expression in the specified language that returns a value.",
      "comment" : "If Expression.expression and Expression.reference are both present, the Expression.expression might just be a name pointing something within the referenced content.",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "string"
      }],
      "condition" : ["exp-1"],
      "isSummary" : true
    },
    {
      "id" : "Expression.reference",
      "path" : "Expression.reference",
      "short" : "Where the expression is found",
      "definition" : "A URI that defines where the expression is found.",
      "comment" : "If both a reference and an expression is found, the reference SHALL point to the same expression.",
      "min" : 0,
      "max" : "1",
      "type" : [{
        "code" : "uri"
      }],
      "condition" : ["exp-1"],
      "isSummary" : true
    }]
  }
}

Usage note: every effort has been made to ensure that the examples are correct and useful, but they are not a normative part of the specification.